I was a believer in D'Addario EXL 170's for a long time, because the sound was good, and I could get them almost anywhere. A year or so ago, I got introduced to the EXP 170's, which are coated rounds. They sound like EXL's that have had about 8 hours of playing on them, and they hold that sound for a long time! I get about 4 times the life than I did on the EXL's, and I think they play a little easier, as well.
As for fretless, I will never put rounds on one again. I wrecked the fingerboard on my Fender, so I have no fretless anymore. My next fretless will only get flats.