I have pro tools and I love it, but if you're just going to use it to fly mr-8 tracking into the computer, you can do it a lot more efficiently with other options.
The one excpetion being the Mbox. Mbox is about as cheap as it gets, concidering you get both the prosumer audio interface and the multitracking software.
The major downfall of Mbox is that there are few upgrade options and no way to add more I/O to the system. You're stuck with 2 inputs and 2 outputs.
If that's all you want to do with it, mbox is a good option. I'd still lean towards a different soundcard and different program, though, because I'll bet you'll want more than 2 I/O sooner or later.
Cheapest program is n-track and does the trick just fine. Even though its the cheapest, its no slouch! Its an amazing value. I can't help with the soundcard, though: I have a laptop and haven't looked into soundcards for a while.
Anwho, to answer your question: I've used n-track, cubasis, cubase VST, Cubase SX, and Pro Tools. I prefer pro tools, but have no illusions that its better than the others- I just like it.
Take care,
Chris