I used Invisalign to fix my teeth in my mid-40s. Yes there are drawbacks, mainly feeling self-concious about wearing them (though no one ever noticed that I was), plus I develped a minor lisp for a short period of time when I first started on my course but I would still recommend them to anyone who is interested. They are easy to use and can always be taken out for an event where you are going to be eating, drinking or speaking a lot. Note that when you have completed your treatment you will need to wear Invisalign retainers at night time.
As for the results, I am very happy with my new straightened teeth, something I was very self-concious about. I understand they they are only really suitable for correcting relatively minor cosmetic imperfections. If you have a serious orthodontic issue then braces are probably the best solution.