aoTuV -q5 is transparent for me (with a pretty wide margin) as is LAME -V0 and 320 kbit CBR, so I don't see a point in having lossless on my DAP.
On my computer, however, I like to have as much as possible in lossless format. Not because it sounds better, but because hard drives are cheap, it's a good archive format, and it can easily be transcoded for different purposes in the future.