I really like how crazy/different the enivorments are from the other maps. Theres a good variety suited to different playing styles in the pack. Mirage really provides balance gameplay, Grind and Hydro a bit more close combat and Downhill long range sniper's paradise.
My preference is for the run and gun opportunites, so my list is:
I really thought I'd like Mirage the best from the trailer, but it turns out Grind its a pretty sweet map.
downhill is big enough to have decent spawns but people spawn 2 metres from where they die, when you have VSATS up on that map you will see what i mean, you kill them then they run right back at you in the middle of a reload >.>