There are a few points you might want to consider before investing in this.
It's not a cheap investment (£2k+) for you, and it's not a cheap treatment for your client. It's not a relaxing treatment either; it can be quite abrasive (hence the name), so they're expecting to be able to drift off and wake up with lovely skin they're going to be disappointed!
Only you know whether your client base would be up for this, and whether you live in an area where the demographic is right.
I live in an affluent village and have a client base of mostly wealthy yummy mummies who can afford to have the treatment, and are quite skin aware.
If you use crystals as opposed to diamond tipped then the client is likely to have a certain amount of skin peeling in 2 - 3 days' time, and it seems that no matter how many times you tell them this they'll still ring you up and fret about it!
There's a heck of a lot of information about microdermabrasion out there, and any number of companies desperate for you to hand over your dosh. Talk to as many companies as you can, try out their machines, check our their credentials, get testimonials from their other customers. Do not get overexcited and buy the one that everyone else has, or buy the entire range of products!
Take your time in making up your mind, and don't fall for any hype that the sales people give you!