I have both a cherry 333 (I think 2002) and a sunburst 335 (from the '80s). I recently bought the 333 because it was in a guitar store used for $900 with a case. It has Lollar Imperials in it, whereas the 335 has the stock Gibson Shaw pickups. The previous owner had the 333 polished and had a 335 pickguard installed. Lacquer polishes up very nicely, and they both have about the same level of gloss. I would be hard-pressed to tell you the practical difference between the two guitars -- they both play and sound amazing. If anything, the sound with the Lollars is clearer and more dynamic -- the neck pickup in particular is to die for, with just the right woody quacky sound. The 333 neck is a medium profile as opposed to the 335's super-thin neck. The access panel makes life simple -- I see no reason not to have it. I love the slightly starker look of the 333 -- the simpler binding and headstock look very dignified. Has a normal tune-o-matic bridge, really nice Gibson Deluxe keystone tuners, tophat knobs with pointers -- what's not to like?
Why the 333 costs about 40% of what a 335 does, I have no clue. It's almost the same thing, and with a few minor mods you can make it essentially identical. Has to be one of the best deals in guitar-dom.
