I've got three ukes. My first is a cheap colored Mahalo soprano with geared tuners. They work fine, but they make the head noticeably heavy. Granted these are probably the cheapest tuners made.
My next uke was a concert Flea with friction tuners. I like them just fine and haven't had any problems. In the beginning I had to slightly tighten the screws a time or two, but it's been fine for a couple of years now. They stay in tune great. There have been a few times where I've let that uke sit unplayed for a few months at a time and when I came back to it, it was still in tune or very close. No complaints.
My third uke is a Mainland concert and I opted for friction tuners. They work great and I've never had a problem tuning, or staying in tune. It really is just a matter of a pinch rather than a twist. Feel the slight "tick" of the peg moving and it's all good.
I just don't like the way geared tuners look on sopranos, and I'm not a big fan of them on concerts either (though it's not terrible). For tenors and baritones gears makes more sense of course, and it doesn't look as odd to me. And though I've only changed strings once or twice, I don't like winding and winding with geared tuners.
But, to each his own.
Jason