I had it done about 7 years ago. Went off without a hitch, though I sort of freaked when he started the 2nd eye. I could smell burning hair, which was the corneal tissue frying.
They tell you to stare at a light while the laser does it's thing. With 2 valiums in me, I ended up staring at the red light instead, until I realised it was the laser. :D
I don't think being 'too old' is an issue. Too young is an issue. If you're eyes are still changing, the surgery will need to be redone at some point. If you go to a reputable surgeon (a.k.a. pay big $$$), you can request the surgery again, for free.
My only side effect is I'm a bit sensitive to light. I wear sunglasses even on cloudy days. Fluorescent lights bug me. I also ended up needing reading glasses, though I don't use them. I just get brighter light bulbs. Lazik doesn't resolve post-40 frequent need for reading glasses.
I'm still 20-25. My biggest problem is buying a lot of sunglasses. Between breaking them, losing them, etc, I must have gone thru 20 of them.
If you're a candidtate, go for it. Check out the facts and your surgeon beforehand though. It would suck to be one of the 3% to 5% that have bad side effects. I reseached the subject for a year and finally went thru it only because I would have lost $3k in deferred medical. I picked the best around - Dr. Fichman near Hartford. He was one of the first in the US to do it and had the latest technology.