Sounds pretty good: I'd say the biggest issue (in my headphones anyway) is a buildup of lower-mids/upper-bass frequencies, which could easily be controlled by some simple EQ'ing.
Arrangement-wise, the whole thing sounds pretty decent, not particularly exciting of course but I'm assuming you're going for the ambient thing so no problem there! The bass guitar line needs some improvement though in my ears: it just doesn't go anywhere, and sitting on the same two notes for as long as it does starts to get annoying to me.
Just my $0.02!
