When I got my Invisalign, there were only two orthondists in the Dallas/Fort Worth area that offered it. I had 22 trays total. My bottom teeth were extremely crowded/crooked and of my two front teeth on top one was crooked overlapping about a third of the other front tooth.
Being one of the first patients my orthodontist had for Invisalign, I did go through a period in the middle of the treatment when they had to use buttons and bands to get one of my top front teeth to drop and straighten out. It was ugly for a while there but its been eight years since my treatment was completed and my teeth are still straight. It works but you truly have to commit to wearing them 22 hours a day - which I did. It helped to switch out the trays before bedtime so my mouth wasn't too sore during the day. I did opt to get a bracket placed behind my top two front teeth to keep them in place and that bracket is still there.
Invisalign is not completely invisable, but it was much less noticeable than braces. I never would have gotten traditional braces as I would have been too self conscious as a professional that gave presentations to clients regularly.