Not to up on Trek
The f300 is nice, but the F400 gives you the headshock. Super smooth travel, but depending on use you may have to rebuild it(the shock) every couple years.
Rockhopper is a pretty nice bike. They beefed uo the frame this year and included the O.R.E. downtube. Bike is kinda heavy for my taste.
How much money you wanna spend? What do you weigh? How agressive do you plan on riding?