I decided to have treatment after pondering it for a long time. I didn't want to wear metal braces because of my age (28 when I started) . A well-known cosmetic dentist made an assessment and told me the treatment would last, based on a computer-generated simulation, around 9 months. What he never told me was that he would put some kind of white "brackets" on some of my teeth so that the teeth could rotate (to this point he added more, totaling 13 teeth with brackets) .
The first few days were really painful and I even developed small bleeding ulcers in my mouth from those "brackets", requiring over-the-counter oral anesthetics. Also, it is worth to know that it can be really painful and difficult to remove the trays during the first couple of days of transitioning to a new tray. After just a few weeks of treatment I started seeing differences and, later on, got a lot of compliments from friends who did NOT know I was wearing them. After 9 months I wasn't 100% satisfied with the results, so my dentist decided to extend the treatment for 5 more months.
Only downside of this would have to be the constant visits to the dentist to have trays delivered, as well as constantly cleaning these trays (word of advise, USE EFFERDENT/POLIDENT TO CLEAN THEM, they get 99.99% cleaned/sterilized without any remaining stains or odors and a box of 120 tabs costs around 4$ and lasts for about a month, depending on how often you clean them).
I would totally recommend this treatment for anyone who doesn't want to wear metal braces, but would tell them that:
1) Can be painful at some points
2) Requires commitment of using it AS LONG AS YOU CAN
3) It can make you lose weight (since you won't be munching as usual since you don't want to mess with invisalign and candy)
4) You may need to get those brackets, which can be painful.
Overall, I'd say I'm very pleased with the results so far and have already recommended this to some of my friends!