I've tried a few, namely Bloog (Chinese), DeKang, Alien Visions, FSUSA, but my favorite is Backwoods Brew. Most are more
tobacco based with a nutty aftertaste. BwB is much more complex than that. It's a more sweet base with nut overtone that finishes with a bit of
tobacco. The FSUSA is good too, and the Bloog is nice--more nutty than sweet. The AVE is subtle--much more than the BwB, and doesn't have the sweet taste. So, I'm a big fan of the 555 from Backwoods Brew, but it's not a typical 555. Interestingly enough, many people who are fans of BwB don't necessarily care for their 555. Taste is remarkably subjective, so it will be interesting to see what kind of recommendations you'll get.
Good luck in finding your favorite 555, and let us know when you do.