I'm with Mark....
....in fact, those are my tuners of choice. Never had a second's trouble with tuning stability.
Quite frankly, in my experience, unless the tuners are REALLY cheap (like the "stamped" ones on the $99 type guitars), nearly all of them work fine. Tuning instability is often something else, such as a poorly filed nut.
"I feel sorry for people who don't drink. When they wake up in the morning, that's as good as they're going to feel all day." -Frank Sinatra