1. The latest Logic 6.4.2 is supposed to have better OMF file exporting. I haven't tried that, but it may make it easier to import sessions into Pro Tools.

2. A better question is whether you have clients who use Logic or other digital audio sequencers. If so, you probably want Logic, DP, and probably Cubase and Sonar for compatibilty.

3. The Mbox is their entry-level hardware, but it uses the same Pro Tools LE software the 002 uses. How good it is depends on what you're doing. If you only have Pro Tools for compatibility, it's more than fine - as long as you don't need more than 32 tracks. You'll find that the 002 sounds better and has more features, but you may not need that.