I've been using eSalon for about a year now.
It's great!
$20 every 6 weeks for my color, and 30 minutes of my time...as opposed to $100 and 3 hrs at a salon.
When I signed up, I picked the color that I thought I wanted, put in some notes, and added a recent picture of myself (with the color I liked from my last stylist visit).
The color they set me up with was literally identical to why my colorist had been using on me.
It's cheap, and honestly, I think I do it better than she did! I can clean up the color left on my skin more effectively than she ever did.
Once you get used to do it yourself, it's a piece of cake!
I also just switched my color a little bit. I entered the changes I wanted on my account before they mixed my regular order. I then got a follow up email from their stylist with the exact changes made, and how to do my application to allow for even-ness.
Huge, huge fan of this service!