[quote name='elros' post='582424' date='Aug 27 2009, 12:38 PM']For bass lines though I'd suggest transposing down an octave or two and playing in the upper register - the tracking is more accurate (timing-wise) there.[/quote]
+1
Lag is likely to be the biggest issue you'll face when recording using a pitch to MIDI interface. It will make getting notes spot on very tricky without using a quantise function and even then you'll lose feel. Alternatively you can teach yourself to compensate for the MIDI lag but it takes practice and even then might not deliver the exact timing you need for recording.
If you're lucky enough to have a bass with the Steve Chick MB4 system installed such as the Wal, Maton or Peavey variants you'll find the tracking and lag is much better but you won't be able to do string bends.
EDIT: I have the Axon AX100 pitch to MIDI and Graphtec GHOST preamp system which, when I have the right strings installed and the sensitivity set up, works really well. Lag is less of an issue because the AX100 has learned to convert the pitch by sensing only half the waveform, unlike other units on the market. However there is still a little lag, enough to make recording a little tricky.