I've experienced two different answers to this question over my years of combing through various 'realistic fiction' depictions of the Age of Sail. Some take the benevolent route, painting sailors as ordinary, hardworking men who enjoy rum and sea shanties, miss their homes, and know how to have fun while getting a lot done. Others depict the life of a sailor as one dominated by dirt, stumbling barfights, and abusive flogging, and the sailors themselves as being demoralized to the point of mutiny. I assume that neither of these viewpoints are entirely correct. Is one more accurate than the other? Would the life of an 18th-century sailor be an exciting adventure, a living hell, or somewhere in between?
I kind of hate answering a question in this way, but the best we can say is "it depends." A sailor in the British Royal Navy, which I study, would have had the opportunity during the 18th century to serve on a variety of ships from those that were very small, such as cutters or brigs with a crew of 50 or less, up to the largest first-rates with a complement of 800 or more.
I would say that if we could speak in generalities, a sailor with a "better" life would likely have intended to join the Navy (that is, not been impressed); be on a ship that was under a long commission with an experienced captain; be on a ship that did not have a large proportion of impressed men or landsmen; and be on a ship with a fairly benevolent first mate. A sailor with a poor life would be more likely to be an impressed man; one who was a member of a large ship, early in its commission, when floggings and petty beatings were common to keep order; one who had the misfortune to serve under a brutal or deranged captain; or one who had the misfortune of serving under a particularly bad first lieutenant.
I should mention perhaps one thing in passing, which is to talk about mutiny: for the vast majority of the time when we have record of mutinies, they were really more in the nature of seagoing strikes, where each side realized they had a grievance and could negotiate to a reasonable compromise. The mutinies aboard the Bounty and Hermione were absolutely one-off affairs; the Hermione mutiny in particular was the work of a deranged man who should never have been entrusted with a command. And the famous mutinies at the Nore and Spithead started in the manner of sailors' strikes, but were met with extreme brutality on the part of the Admiralty which feared for the very existence of Britain if the Channel Fleet would not come out and fight.
I've linked below some relevant answers about life in the RN. Please feel free to follow up with more questions.
https://www.reddit.com/r/AskHistorians/comments/2oo91z/during_the_age_of_sail_how_reliable_were/
https://www.reddit.com/r/AskHistorians/comments/3pn7v5/what_changes_occurred_in_the_construction/
https://www.reddit.com/r/AskHistorians/comments/1kmyo6/during_the_age_of_sail_how_did_life_for_both/