You know? This question definitely deserves something in-depth. I've got a couple of answers on this very thing that I've written about before (here and here), but clicking through links takes time and energy, and I might as well spruce those up a little bit to be more encompassing. Much of the content- especially from that second link - I'll go ahead and just put in this thread as well. There's some good material there ;)

First off, I'll address Netflix's version. I always like going through bad news first. The first season (Commodus) was, for me, ultimately forgettable. It was a mediocre docudrama that I might have expected to find on the History Channel. The intro was, frankly, the best part about it - it's a tamed down version of the actual history of the character himself. There was nothing special about it, but nothing particularly awful, unless you count things like them not noting things like Commodus' glorious titulature (which I'm obviously about to give you a sample of):

Imperator Caesar, son of the divine Marcus Antoninus Pius Germanicus Sarmaticus, grandson of the divine Pius, great-grandson of the divine Hadrianus, descendant of the divine Traianus Parthicus and of the divine Nerva, Marcus Aurelius Commodus Antoninus Pius Felix Augustus Sarmaticus Germanicus Maximus Britannicus, pontifex maximus, holder of the tribunician power for the fifteenth time, imperator for the eighth time, consul for the sixth time, pater patriae, greets the magistrates, city council, and people of Boubon.

And you thought that Daenarys had a long title. Anyway, so that's my generic thoughts on the first season. The second season was....awful. They clearly got the "eh" reviews from S1 and the director of S2 decided that he wanted to jazz things up by ignoring history and historians and going with his own (made-up) story that, frankly, was far less interesting (both in writing and in plot) than Julius Caesar's actual life. This is where the first post I linked comes in - it's an extensive discussion of what they got wrong, what they could have done, and why it makes me so unbelievably angry. I'll see if I can condense that up a bit for you here, but...frankly...read that post if you want to just see me pouring out anger over the abomination that they made, along with some quotes from the actual source material.

When watching it, assume that everything you see is blatantly wrong. While S1 and 3 at least pretend to remain faithful to the source material (without any pesky historical analysis), S2 goes completely off the rails. You know those quotes from historians? They're taken blatantly out of context with no shame whatsoever to support the narrative that the director wants to push. To just focus on some things that they lied about...

Caesar, at 19 (when the show purportedly starts), did not work his way up from the bottom of the military, as the show uhm....makes up out of goddamn nowhere. [as noted below, he did spend some time in the retinue of the governor of Asia - a standard position for an aristocrat looking to be electable]. His father was certainly no traitor to the Roman state, Caesar's family did not lose their fortune as a result of a treason (since it never happened) - they just weren't a wealthy patrician branch to begin with. Rather than "working his way up the ranks in the army," Caesar spent a little bit in hiding because he rubbed Sulla (bloodthirsty dictator) the wrong way by refusing to divorce his wife. He was captured by Sullan soldiers at one point, bribing them to let it go. After they let him go, he made his way to Bithynia, had an exceptional amount of sex (allegedly) with the king, started sailing back to Rome, got captured by pirates, paid his own ransom, raised a small army, went back and crucified all the pirates, made his way back, went back to Bithynia (heh), and eventually made his way back to Rome to start his cursus honorum, during which he continued his career as a...uh....player. Having sex with everything that moved.

Instead of all this, the show decides to go with "he worked his way up through the ranks of the army and was the key strategic mind behind defeating Spartacus." For the record, we have no evidence that he had anything to do with the Spartacus War. Also Caesar had neither a beard nor pants. I have serious issues with the costuming on the show, especially when they decide that the viewers are too stupid to differentiate characters if they change clothes at any point in time. Speaking of time, the show likes to straight up ignore it. Around the time of Caesar's consulship, for example, Servilia would not be a hot young supermodel fox lady. She would be about 40 years old. Her son was born in 85 BCE. He would be in his 20s. Julius Caesar would not have stumbled (shamefully, because we all know that he was a family man) out of Servilia's bed and bumped into a 6 year old Brutus, because Julius Caesar was off being sodomized in the East at that particular time. Nobody likes memorizing dates. But you know, when you completely and totally disregard them, shit like this happens. ALSO, not only would Brutus and Caesar probably have known each other at least vaguely by this point, our dear Brutus would not have introduced himself as....Brutus. That's literally the least helpful introduction he could have used. It's the equivalent of someone asking your name, and you tell them a family nickname. Not a nomen, not a praenomen, but a cognomen, which is about as useful as nipples on a breastplate when you're meeting someone for the "first time."

For all those faults, though, the most egregious - and unforgivable - is the way the show casts itself. Your very question shows the uncertainty involved here. Is it a documentary? It has all of these talking head people with fancy titles. Look! Clifford Ando! From the University of Chicago! And then there's another guy who talks real fancy! These talking heads convey the sense that there's historical accuracy involved - it's similar to the History Channel, isn't it? The show dramatizes things, but holds to the narrative of these bona fide historians, no?

...no. If you watch carefully, you'll notice that the actual professors have their talking very selectively edited. They were clearly answering questions about something completely unrelated, but their words sound good to support <insert unsubstantiated point>, and therefore their words go here. One example is with the aforementioned Ando, who is edited into the Spartacus bullshit to make it seem more "truthful" or "real." Watch it again and you'll notice they never show him mentioning Caesar and Spartacus in the same sentence. Because they weren't. They had nothing to do with each other, other than their living in the same-ish place, at the same-ish time. The only...source, if you want to call it that, that I've seen that suggests such a thing is the TV show, Spartacus which, while fun to watch, literally made everything up around the incredibly sparse and bare framework that we have around the life of said gladiator.

If I knew how to contact whomever made this show with a review, I would. I would tear them a new one for deliberately spreading misinformation in an age where the truth is more valuable than ever, and enough people make up their own goddamn narratives about history to fit whatever argument they're having on Facebook. Things like this are the last thing we need - especially when the actual source material itself could easily just be transliterated to the screen. No talking heads necessary. There aren't even that many blanks to fill - we know a ton about Caesar. All it would take is an iota of respect for a basic research job that any halfway competent grad student could have done - and would have done for a paltry price.

I'll give you some context. I adore Spartacus. I love HBO's Rome. The great difference here: Neither of them proffers themselves as an accurate documentary (which this one VERY MUCH does). HBO's Rome is infinitely more historically accurate, and yet eschews the talking heads adding credibility. A historical fiction is far more interesting, far more engaging, and far less of a bald faced, blatant lie. Something that pretends to be "historical" - as this series does - ought to actually...yknow...follow the source material. As is, I wouldn't recommend the show to someone I actively dislike, let alone anyone who I want to have any interest in history whatsoever. If the show was not meant to be judged for its historicity, then it ought not have pretended to be history.