Original arrangement may sound great but sheet music sounds bad...

It isn't right that when I arrange something to piano is sounds great but if I make a sheet music I can't get the timing good enough Mainly because I have to do it by hand I have no way or real time recording. That would solve all my sheet music problems if I could record it live and then the computer transcribes it but I don't know how people do that. Anyone else have this problem? Then again I guess it could be because if I can't read it it dosen't work backwards either. Meaning if you can't read a sychopated rhythm then you can't transcribe it either.

I record in FruityLoops, and export what I've play'd into midi. But this doesnt always get correct, and you'll have to do some manual editing.