GOW1 Classic
GOW2 Classic, but the lagswitch fukked everything up. the ranking system was GOAT but the update fukked everything up
GOW3 they fukked everything up basically decided next gen was more important
Gears 3 >>> Gears 2
Gears 2 was the worst one simply because of how retarded the nades became with the tagging and how the smoke nades would knock people down and make them have seizures
But honestly, the reason Gears as a whole became less popular is because COD came out and changed the game. There weren't any other heavy hitting online games out at the time of Gears 1's release, so everybody was on that shyt. Now there are a lot of easier alternatives and people aren't stuck with just playing Gears.