Hi Neil ... I'm with everyone else. I'm not sure what stage you're at with your playing, but if you do feel that you've got the basic down and now you've reached a plateau, then
PT will certainly give you plenty to work on and a whole new way of looking at the fretboard, one that will last forever.
I used to do some pretty decent recordings with a cheap PC mic and I did try a couple of other medium range mics too without much improvement. You've really got to go up a few notches to really hear the difference with mics. So much has to do with mic placement, levels, background noise, eq ... no matter how expensive the mic you're using. I'd hold off until you can get a really good one, myself.