interface for guitar recording??
 

I've been looking to get an Interface for awhile now.
Max price ~$150(USD)
I have narrowed it down to these four:

Samson G-Track
Presonus Audiobox
Line 6 UX2
Focusrite Saffire 6

When I google your products one doesn't fit the list. The Samson G-Track comes up as a microphone. Might make for a great recording device but that's not at all the same functionality as a recording interface. Presonus and Line6 have the most recognizable reputations and you'll get what you pay for with their stuff. Can't comment on Focusrite.

Personally I have an M-Audio Fast Track Pro - M-AUDIO - Fast Track Pro - 4 x 4 Mobile USB Audio/MIDI Interface with Preamps . It seems to offer about the same functionality as most of the other products you list. Same price range too. My device also came packaged with a demo versions of Pro Tools as well as two versions of Abelton Live. There were also had some upgrade coupons in the box for the software but I haven't used it in a while.

Either way, they're all decent enough devices, and assuming you're just looking for something to record basic guitar tracks / song ideas then just go with whichever one provides the best hardware/software package.