My string of choice for over 20 years. A nice compromise between that edgy round sound, and undamaged frets. They aren't quite as smooth as flats, but they are easy to play. My only gripe is that they no longer come in a medium gauge - they go from the .098 E set right to the .105, and I like the .100 best. I've switched to the .098 on my Epiphone, and they're fine. GHS also makes these for extra-long scale necks, another plus.
I've never tried their flats. The Brite Flats are a little darker than the D'Addario and a little smoother than LaBella Hand Polished Quarter Rounds. They are an excellent choice. I like them for fingers and pick on classic rock.
For you fans of GHS brite flats, do yourself a favor and TRY a set of GHS pressurewounds. You may be pleasantly surprised, I was.
I put a set of .100 Pressurewounds on my Hamer. Really nice strings, but I still prefer the Brite Flats.