I think I need a looper. JM-4, Digitech Jamman, etc?

[yumanike]

Ok, bear with me. I'm new, but I know enough to be dangerous. What I am looking to do is lay down 12 to 16 bar blues using chords. Then play that back and solo over it, while recording that. Then I want to put that into the computer (and maybe a DAW) so I will have it forever and ever but also be able to take it different places with me. I'm looking at the JM4 and the Digitech Jamman. For the foreseeable future, this will only be used for practice and not in a live setting. I'm trying to keep it under $350. I have searched this forum and a few others and I get many mixed reviews for both. I currently have a G-Dec 30 and will be borrowing a Fender Twin Reverb (because I have awesome friends!) and I have the following questions.
1. How easy will it be to get my loops from the looper into the computer and hopefully a DAW?
2.What do you think of the JM4 and the Jamman? Other suggestions?
3.Is there a setting on the JM4 where it will not color the sound comming out of the amp? I'm guessing this isn't an issue with the Jamman.
4.With these units can I lay down a chord progression, then a solo, then vocals, etc. I know the boomerang III has 3 loops, but as I said, I'm new and I don't understand the difference between that feature and the 99 on the Jamman.
5.Did I leave out any information?

Any help is much appreciated! I come here first because I like the information the best!