All of those forks are only fair, they are all coil spring forks, only really suitable for smooth trails. Certainly it is possible to manage with a lesser fork, but I would suggest something with a full air fork. If you are comfortable doing your own wrenching, bikesdirect.com has the Motobecane Fantom29 comp wtih a full air fork for $799. Motobecanes are solid frames, a bit heavier than Giant or Specialized but decent. My son has one.

For specialized the Rockhopper expert is the first model with full air fork at $900, most other brands it is $1000 for the first full air fork.