Just got mine (25 yrs) this week, not invisalign since my teeth were/are movie monster bad, so that just wasn't an option. My friends sister got invisalign and it worked really well for her in a short time apparently(though I don't think they were that bad to begin with.
I'm on some very noticable(compared to invisalign) damon 3 system, it'll be about 6k when I'm finished; supposed to work in 12 months though if everything goes alright.
I'd say i wish I got these as a kid, but really, when I was a kid I would have to have had them on for like 3 years, so glad I waited for the technology to improve. it's a hassle, it sucks, and socially it's probably embarressing, but I'm an adult(more or less) now so what do I care, I have screwed up teeth, and I'm getting them fixed.