1: An extremely rough work that has aged very, very badly. The thing I could never get past was how relentlessly IRRITATING it was. Beggars who’d swarm around you and whine their heads off, preachers who’d blather the same six sentences over and over and over and over, derelicts who’d (stop me if you’ve heard all this before :)) smack you around for no damn reason, and any attempt to curtail any of this was at best temporary and would frequently worsen the situation or even cause you to desync. Oh yeah, historical inaccuracy and boring combat blah blah etc.
2: A masterpiece. Strangely enough, I think the main reason was that it came at the right time: Ubisoft got rid of everything that didn’t work in 1 but hadn’t yet fallen into the hardcore/multiplayer abyss. Thoroughly enjoyable from start to finish and extraordinarily satisfying. I must have did six complete playthroughs. This and 1 were the only two, incidentally, where I got 100% achievements (this one on PS3, the other on X-Box 360).
Brotherhood: Not quite as wonderful as 2, but still tons of fun, and Ezio’s new abilities absolutely rock. Definitely get the bonus content; worth every penny.
Revelations: Another step down, but still pretty good; loved using the hookblade, although getting bombs to work was a bit of a chore.
3: Did a lot of things right, actually enjoyed this more than Revelations, but ultimately there were too many dealbreakers…glitches preventing the sacking of wagons, some tasks were flat-out impossible (the execution scene is an endless nightmare if you’re going for the optional tasks)…and the games. The friggin’, friggin’, friggin’ games. DAMN THE GAMES TO HELL.
Which brings us to Black Flag. It fixed some of the problems from 3 (games are completely unnecessary, you have more options in combat, games are completely unnecessary, optional tasks are less brutal, games are completely unnecessary, and did I mention that games are completely unnecessary?) and is richer and has more depth overall. There’s tons of stuff to explore; you can easily spend hours just finding treasure and building up your fleet. One thing that I think deserves special mention (which almost nobody else ever brings up, alas) are the Epic Ships. These are completely optional, and if you take them on, they will fray your every nerve and frustrate you to the breaking point…BUT if you’re calm, persistent, and patient, you will eventually best them, and the feeling of accomplishment will be incredible. I can count the games that successfully pulled this off on one hand. The usual method is to just make the game ridiculously hard and shovel it out the door. To make a challenge that’s JUUUUUST hard enough to be close to impossible yet give the player incentive to keep fighting on until the moment of triumph takes real effort.
The only real downsides I can think of is that way too much is tied to multiplayer and the network (good luck finding any white whales now) and unlike the previous games there’s no way to generate steady income. You have to be a virtual kleptomanic to get anywhere, and you cannot ever pass up a chance to upgrade your ship.
In all, a big thumbs-up from me. I doubt you’ll be disappointed.
As for the rest: Rogue might be worth it if you can get it really cheap. Otherwise don’t bother; too small and limited. Unity…I’ll make it as simple as I can. NO. You will hate it. Trust me, glitches, clunky stealth mechanics, and Arno’s dubious motivations are just the beginning of the endless, massive, gaping problems with this game. Unity is absolute crap. AVOID. (Here, just read this.) I haven’t really gotten into Syndicate yet; from what I’ve seen, combat is way harder than before and you have much less margin for error. If this is the direction AC is going, I may have to give it up. I’d recommend it only if you have a lot of patience.