I get a microdermabrasion about 3 - 4 times a year. Everytime I've done this other women (and some men!) ask what I've done to my skin - it looks great! (by the way I am 53 and easily look 10 years younger!) As an add-on to a facial it works very nicely as well.
Don't expect this procedure to get rid of your wrinkles although it may minimize very fine lines. What is does do is make your skin look healthier by improving the overall texture. I think that some of the people who were disappointed were expecting too much.
One time I tried it at another spa in NYC and wasn't as pleased with the results - the machine was too harsh and ultimately I couldn't see much of a difference afterward. I guess sometimes you get what you pay for.