I did invisalign for a few different reasons... One being that as a kid I didn't wear those horrid cheap plastic retainers they give you after braces. Two because my friend had just completed her treatment and her teeth looked fabulous! Three because I was on a weight loss make myself look better routine and that included my teeth.
I was worried that since I didn't like the plastic retainers as a kid I was going to have a problem with these. I can assure you that they are totally different and I don't feel them around my gum lines like the others!
Pros: People don't see them, really! My boyfriend of 5 months at the time asked me are you wearing your teeth as we affectionately call them... and I was. They don't hurt for very long after each new tray.. 24-48 hours. and the further along you get you get used it. They also are great for losing weight. It becomes a pain to take them in and out if you are a snacker like I used to be so you just stop taking them out and you start eating less.
Cons: none really except that if you are a mouth breather they will tend to gunk up in the night and it will be over the front of them in the morning. Morning breath can be particularly gross too with them, more so than normal. I am on tray 21 of 23 and love where my teeth are! I totally recommend them!