In my honest opinion, all of those bikes won't last very long. They're department store bikes.
I got my Diamondback from Dick's, and it's a good bike. Much better than those listed above. But definitely has its bad sides.
My advice, forget department stores. Go to a real bike shop and search for a decent hardtail. My friend got a specialized Rockhopper Disc for around 500. And maybe you could work a deal with them on some of the bikes that have cosmetic damage from shipping. Normally bike shops will sell bikes like that for pennies on the dollar.
I learned this because I've been having troubles with the department store thing ( I had a thread posted about it), and I've learned that I'm never gonna buy a department store bike, ever again.