they are a challenge, to say the least. You'll never get them shifting perfectly, but if you work at it you can get reasonably close. And just think of the adventure...you never know if the next shift is gonna complete gracefully. The only thing that I can guarantee is that if there's a babe anywhere within earshot, you're gonna grind a pound of gears with as much noise as a bike can make...
you need a bike set up with these shifters, if for no other reason than to remember how good modern shifters work. If you set up a nuovo or a super record, you also need the adjuster barrel that allows you to fine tune the cable tension. That piece was actually part of the upgrade kit to synchro...if you buy a NOS set make sure that the little adjuster barrel is in there.