I like both, but not EVERYTHING about either. And I sometimes wonder if I honestly prefer one over the other. I'll explain... Armored Core 4: -The next gen game I wanted to play more than anything else. Didn't buy it for a while cuz I didn't own a PS3 then but when I did finally get it, there was still a sizeable number of people playing so the online was fun. -To me, what AC4 had over FA was the story, which seemed alot more engaging to me than the latter's story. To be more clear; your characters actions in AC4 seemed to be alot more significant, especially given the more challenging game mechanics and what was going on in the story in general. Kind of ironic that I collapsed RayLeonard when I was such a big customer of theirs hah! -The gameplay was too similar to FA to really make any worthwhile comparisons but I agree that the lack of infinite flight, etc. seemed to make AC4 more challenging compared to ACFA: I took my lumps coming up in AC4 and then when ACFA came out, I almost breezed through it easily due to the easier energy mechanics. Armored Core For Answer: -Same fun online as AC4 at first, then when the lag became more apparent the fun slowly dissipated. -Now what ACFA lacked in story compared to AC4 it made up for it in scale of enemies (the arms forts, though they turned out to be big pushovers more than anything) and one very important detail: co-op missions. Seriously, that made a big world of difference, especially during the heyday of FA's online portion when you could always find a few competitive matches and partnerships going at almost all hours of the day. I know alot of people take it for granted but to me, the only thing more fun than stomping obscene amounts of ass in a big mech is to do so with a friend and I did that alot before the online mode died off. -The infinite flight mechanic kind of seemed cool at first but after a while it got old. Even the assault armor feature didn't get used by me as much as I would've liked due to being so used to simply rolling with a pure-OB booster. These days I only own and play ACFA but I'm beginning to consider tracking down AC4 just to run through the story again. Thats my 2 cents.