The M-Box bundled with PT LE 8 is a far better deal. I am an M-Powered user but for the smaller interfaces, the software alone is 249 dollars plus your m-audio interface. There is no upgrade path from SE/Essentials. Also if you choose to upgrade to ver 9 the LE - 9 crossgrade is $100 cheaper than the m-powered one. If you are concerned about preamps, then the M-Box 3 , or the Firewire M-Audio stuff is better IMO. But Preamps are opinion based so do your own research on that. (We aren't talking apogee here :))
Edit: Guitar Center has
THIS. MBox 2 Mini with PT 9 Crossgrade for $439. That's a good deal.