Note: We don't recommend these for 10/11-speed rigs or with modern SRAM derailers, which have an "actuation" ratio that's different. We haven't tested them with those, and have no interest in those. It's kind of a matter of: Pick your solar system and stick with it, do things that others in that solar system do.
These are the best shifters you'll ever set a hand on. There's nothing like them, and if you think your old SunTour barcons are the bee's knees, bless you, but you're living in dreamland.
Their magic is the Power Ratchet inside. The old SunTours had that, too, but this Power Ratchet is a big improvement over that one (and since that one was already fine, this one...must be superfine.) The shifting is smooth, light, simple, fast, and precise. Indexing, in comparison, seems raucous and archaic. They work with any derailleur, and freewheel, cassette, chain, etc., so you have the peace of mind that comes from knowing you'll never be midway between gears and powerless to do anything about it.
There's a short learning curve, but don't let that scare you. Everybody learns fast with these.
The downtubers come just the shifters, because you don't need all the other monkey business. You'll still need cables and a little piece of housing, though. You may already have them, your LBS definitely does, and we definitely do, too.
Silver shifters now include new and improved washers that are thicker and made out of UV resistant Black or Dark Grey plastic.
Silver shifters are all aluminum, guts various metals, 'cept for the two plastic washers.