Gears 1, I mostly played the single player campaign. FPS give me headaches if I play for longer than 10 minutes, so my only choice is third person shooters and there aren't many choices out there. The multiplayer option on Gears 1 wasn't that fun for me. Maybe it was because I started playing it late, but it seemed to be just little kids screaming obscenities with no sense of team play.
I bought Gears 2 shortly after launch and played through the campaign twice (casual and insane). I probably average 3-4 gaming sessions a month of about 2-3 hours each, so I took me a while to play through it. After that I checked out the multiplayer options. Horde was a great idea, but poorly implemented at first. You started out with 5 players, but inevitably people would get bored and leave the match and you'd end up with 2-4 players trying to struggle past level 10 or so. Thankfully with the Social match option they've finally fixed that and matchmaking has players join the game at any point.
Eventually I got bored with Horde and moved on to Execution/Warfare but that's not a great game for a beginner to learn with. I got tired of being constantly killed and then waiting for the round to be over with so I could be quickly killed again. Annex was what I finally settled into since players constantly respawn after being killed (Submission/King Of The Hill and Guardian [somewhat] are the same way).
I read the Epic forums from time to time and saw all the complaints of hacked matches (point totals reaching the billions per match), modded controllers (rapid fire by default), bridging host (to ensure the advantage of having host for a person), glitching, etc, etc. Personally the only one that ever affected me was the host bridgers. Epic took care of them with a title update a while ago. Of the almost 1000 matches I've played, I had someone glitch out of the map once, I had someone use a lag switch maybe three times (though I can't count the number of times losing teammates would accuse the host of lagswitching, sore losers will always find some way to shift the blame from their own gameplay). Maybe its because I play Annex almost exclusively, but I really haven't seen any cheating. Epic has made 6 Title Updates so far, fixing issues related to game play and potential ways to cheat with each one. They definitely listen to the community, almost to a fault. Seems the GOW2 forum has a ton of sway when it comes to changes made to the game for each TU.