I hate to admit it, but I have used pretty much strictly Rotosounds since I got my Epic in 1995. Sure, the Alembic strings are also great, but hard to come by. I have also found that the Rotosounds have a distinctive growl that all the other strings I have tried do not. I have also used elixirs, d'addarios, DR's, GHS, ernie balls, etc. but always wind up going back to the rotosounds. I have never had a set break, unlike the D'Addarios. I used to pop my G in two every week (.45 gauge too!).
I haven't had many problems with the rotosounds damaging the frets on the Epic, and there is also a set on my new Excel as well. I can say that the rotosounds are hard on your fingers if you haven't played for a while. I got a nice new blister/callous on my right middle finger to thank them for. Oh well, won't blister again!
I currently have a set of GHS Bass Boomers on my Geddy Lee jazz bass (130-50 gauge), but don't really like them. Then again, I don't really like my Geddy anymore after picking up my Epic and new Excel.........
I prefer stainless because I destroy nickel strings (sweat!) after about a week or two.