So this is a pretty tricky question, and to give a quick preview I'm going to give a bunch of reasons why "yes" is a good answer before eventually saying "no".

To step back a bit, we should first get a good handle on what the Roman Empire was as opposed to what it did. The Roman Empire was, in its heart, the political unification of the entire Mediterranean basin for the only time in history and its combination with interior Europe west of the Rhine. If you study European history you will see why this is such a momentous achievement, as the Mediterranean continued to play an incalculably important role in global history. This political unification, for whatever reason (the debate is long and out of place here, but I would be happy to go into it) led to an enormous expansion in production and exchange of a whole variety of goods. Regional patterns of consumption persisted of course (one finds more Gallic pottery in Britain than Egyptian pottery) but there is a certain comparison to be made to modern globalization. Not to the level of all ball barings made in a single factory in Germany of course, but North African pottery, for example, reached everywhere in the empire. To give two examples: black pepper could at this point only be produced in India, and reached the Roman Empire largely through the Red Sea ports of Egypt. Yet pepper is found not only in Egypt and in Italy, but also along the border with Caledonia in Britain and in northern France. Another example are bronze surgical instruments (which are pretty cool to look at, they have a lot of similarities to modern tools), particularly the Syrian bronze maker Agathangelus, who has instruments stamped with his mark as far away as Pompeii and London. There are plenty more "gee whiz" examples of the wide distribution of goods, but these two in particular are interesting because they carry a lot f cultural baggage. The surgeon in London was not merely using tools that came from Syria, he was therefore practicing medicine in a way that made use of the same tools that someone from Syria would. Same with the pepper, which indicates a transformation of palate.

A lot of this increased material prosperity went to the rich, who were rich in a way that probably wasn't duplicated by westerners until industrialism, or at least the colonial companies. The vast fortunes created by the empire funded an incredible array of artistic creation (think of a Greek statue: that statue is actually a Roman "copy", and there are a thousand of them) which is still visible all across the Mediterranean. There are countless massive Roman cities that are simple empty today (Perge, Aspendos, Hieropolis, to name three great ones from Turkey), and many of the major still existing cities have a Roman layer. But this also affected the poor, as even peasant houses in the countryside had better made tile roofs and used superior dining ware than previous or later periods. To go down to a very small scale, examination of cow bones has shown that cows during the Roman period were bigger and fatter than in previous and later periods.

But did that make people's lives better? And that is where all this runs into a pretty startlingly powerful contrary piece of evidence: the examination of skeletal remains show that, on average, Roman had a lower standard of living (worse nutrition, more disease, shorter lifespans) than people in the Iron Age and early Medieval period. It isn't conclusive, but it refocuses our way of thinking of things. Peasants may have had nicer plates, sure, but they might also have had more overweening landlords and less farmland. A person in Britain could get Italian wine, but also Roman taxation. Roman soldiers may have ended large scale warfare, but they could also brutalize the population. And so on.

There are plenty of ways to look at this. The study of bones for standard of living measurements is relatively new and thus the data is unstable, the study of settlement patterns is not, and the movement of settlements from the defensible uplands to the fertile lowlands is pretty clear and universal. If you favor not having to flee to the hills from raids and invasion that seems like a positive development. But I also didn't even mention slavery, which the Romans did not invent but did bring to new heights (it is possible that the Roman slave trade was as large and destructive as the Atlantic one, although this relies on fiddly demographic arguments). There is no simple answer to whether the Roman empire was "good" or not, but I would say that, by and large, the empire made communities more peaceful but less free, more materially abundant but also more impoverished, there were more exotic goods but also more exotic diseases.

The bit about standards of living come from here. The bits about the economy come from a lot of places, but Emanuel Mayer's Ancient Middle Classes, Peter Temin's Roman Market Economy and Peter Bang's Roman Bazaar each present very different perspectives. The bit about settlements comes from, among others, Kevin Greene's Archaeology and the Roman Economy.

EDIT: OK, looking over this it looks like I didn't really directly answer your question. Regarding the fall, I will sidestep the whole debate about what the fall was (maybe it didn't fall, but the damndest thing happened to it in the late fifth century) and just sketch two perspectives. Brian Ward-Perkins Fall of Rome End of Civilization takes a dim view of said damndest thing, as he primarily looks at the flow of goods and material production, and Christopher Wickham's Framing the Middle Ages, who takes a decidedly less dim view as he focuses mostly on things like communal autonomy and systems of imperial control. Classical archaeologists tend to prefer the former, late Antique social historians the latter. Both camps tend to talk past or dismiss one another. (I'm not being entirely fair here, of course).

My sympathies to /u/tiako handling this very complicated question by himself.

So the answer to your problem (as usual, as always) depends upon defining "quality of life." It depends upon who you're talking about (what socio-economic class) and what constitutes quality (material? autonomy?).

Because we exist in a capitalist society that values material and a material understanding of comfort, our ideas about the quality of life are tied to that. Do you have access to commercial goods? Do you have a soft bed to sleep on? Do you have access to medicines that will prolong your life?

But at the same time, we also exist in a culture that values autonomy and agency. I mean, what is the point of the movie Braveheart except "FREEEEDOOOOOM." At the same time we value wealth, we the idea behind "better to die on your feet rather than live on your knees".

This isn't merely theoretical, this applies directly to the analysis of the transformation of the Late Roman world to the Early Medieval world. In a nutshell, the standpoints I just laid out are the arguments of two books Tiako has cited, Ward-Perkins and Wickham.

Ward-Perkins makes the judgment that because material comfort has declined, quality of life has declined. Key to his argument is that although the late Roman system was intensely biased towards the rich Roman 1%, the productive capacity of the empire allowed high quality low cost goods to trickle down to the peasant.

However, Wickham, points out that the collapse of the Roman exchange system and the collapse of the wealth of the Roman 1% (my words, not his), meant the coercive level of wealth extraction by powerful landlords to peasants was reduced, simply because they no longer had the power of a unified Roman state to back them. What this means is, though the average peasant (who was always 80-90% of the Roman population) had less access to material goods, what he lost in "stuff" he gained in "freedom." No longer did he HAVE to give up all his crops to his landlord, and although life expectancy might be shorter, he could work with little supervision beyond his own.

In the interests of being neutral, I won't comment on which position is the better one. But it's important to remember both are valid, and both are positions reflected in the arguments we carry on to this very day about the quality as well as the purpose of life.