#2
Not too sure about what that does, but to record guitar and vocals i just run them through my multieffects (Korg ax1000), into the microphone input in my computer. Pretty decent quality n everything, and sounds like pretty much what you want.
Sig
#3
i might be looking at the Zoom G2.1u which has a USB interface built in an effects.Good buy? i think it will be better than my previous ubs interface
My Gear:

Schecter Hellraiser C-1 FR (EMG 85/81)
Mesa Boogie Stiletto Deuce
LOPO Custom 2x12 (Celestion V30s)
#4
a mixer is for bringing multiple instruments together and setting the levels and EQ on each of them before sending it somewhere else. that somewhere else can be a PA, your computer, or anything else that has a line in. that mixer looks to have a USB connection so you can easily attach it to your computer and use it for recording. it even says: USB Interface for recording the output directly to a PC, and right under that it says 100 digital effects. it should do what you want.
#5
would it be better than a Zoom G2.1u?
My Gear:

Schecter Hellraiser C-1 FR (EMG 85/81)
Mesa Boogie Stiletto Deuce
LOPO Custom 2x12 (Celestion V30s)