I've had Wash and Coinmach. Got to say that I was not happy with either one. There are 2 approaches:
1. They own the machines and collect the coins and share with the owner at the negotiated rate
2. They own the machines and you, the owner, pay them a monthly rental fee. You collect all the coins and there is no sharing back with either vendor.
I have both options. In the first instance, I really see that I am leaving money on the table. Also, their contracts are very favorable to them and stays with the property even after you sell it. So I am stuck with them for a while in one of my buildings.
In the second instance, I found them to be quick the first few times there was an issue, but after that when the same issue (not working washer) repeated, they started to say that it was my issue as the owner for faulty plumbing. Needless to say, I got rid of them and bought my own washer and dryer. And of course, now they work fine with no issues (with the same plumbing).
My recommendation would be to buy your own and if you don't want that, rent machines.