kinda difficult to answer, it depends all on how you boost and what kinda of multipliers Epic is offering. I will say this though, I originally did my Vet Gear ach. during a 20xp event and it only took 12 hours to go from basically nothing to rank 100. When I did FEAR 2 4 star ach. it took around 60 hours to complete and that's only if you have 2 ppl using 2 Xbox's. Both of these achievements are Hell if boosted ordinarily with no XP events or double Xbox's though and I don't know who would win that contest. But it's safe to say that Gears 2 Vet Gear is easier as long as you have a multiplier 20 or better, but it does require 2 more ppl to boost as opposed to Fear2 where you only need 4 to start a game.