Firing Range. The name says it all, its literally designed to be what its used for, even though the others are as well they usually have some loose cameo-style theme relation to campaign missions and the like. That's just a moot attribute, I know, but its also very well layed out with lots of varied-range opportunities, none of the campsites really seem to be that overly defensible making them require more skill to exploit and the range structures themselves, riddled with cut outs and second looks makes for an added edge of your seat feel. Summit is also one of my favorites and crisis is a good balance for size and terrain.