Well, my 335 is probably my favorite guitar and there is nothing even close to "mud" in the sound. I think the problem you had was that the guitars you were trying are equipped with those Gibson ceramic pickups. They sound like garbage in my opinion. I find '57 Classics and the new Burstbuckers to have a very warm, clear sound through a clean amp.
If you really want to like Gibsons (and for the price I don't know why
) I'd suggest checking out the 335. It is very versatile and has a beautiful tone. The VOS series Les Pauls are pretty nice, too. Way too much coin, though.
You might hear "muddy" when I'm hearing "warm" and that debate is as old as the wood from which the guitars are made. Telecasters can sound too "plunky" or compressed to me sometimes when played clean. Granted, there are a ton of folks on this site that specifically look for that percussive tele tone and that's cool, too.
Good luck with the Gibbers.