M-Audio, in my books, are low level entry stuff, and £50 seems cheap for something like that.
I paid £350 for my interface when I bought it about 2 years ago, but it's worth the money.
Focusrite Saffire
The best bit about it is, it's portable, and gets a great sound for live samples. The midi is very quick, and the interface has never crashed. You'd be fed up of the lag, and crap quality audio on the M-Audio stuff quite quickly.
Focusrite do a LE (Lite) version of the Saffire, which is about £100 less, and they pop up 2nd hand a lot.
Seriously, don't buy M-Audio for interfaces, only for keyboards.
If you want any demos of the quality of the Focusrite, PM me and I'll pop a MP3 over.
Keyboard seems fine, Alesis have nice feeling keyboards.
P.S. - Recording your live sets with the focusrite would be easy as it can take a huge frequency band in and it's a mission to get it to distort.