Warning: Invisalign is not the cheapest of procedures, but I trust them 100% based on my results. You need to manage your own expectations of the costs and be sure to ask up front what each treatment will cost, and any potential costs involved (x-rays, hygienist) so you are informed.
I have been a patient for almost 9 months for Invisalign, and I am thoroughly happy with the results. I did have to invest more than I initially expected, but it's one of those things - once you start, you might as well continue to the best possible outcome if your savings permit.
On multiple visits, the staff are always polite and friendly. There are usually a number of options available when booking an appointment, which is great - means they're don't over book their calendar. There was only 1 occasion when I could not get hold of the Dr as he was on leave, and delayed my treatment progress for a few weeks; but hardly an issue given the results. They respond to email queries in good time. And they offer a referral programme for your friends and family.