Maybe thoughts are different in your area, but IMHO, concrete has NO place in the landscape, especially residential, as far as edging is concerned. Be it "bullet" type edgers or curbing.
Not only does it look tacky (just like red mulch, YUCK!), it also does not allow easy re-shaping of beds in the future. Imagine a customer spending $1k or more (what does that sh*t typically run, anyway?) on edging, only to want to expand the beds in a few years. Hmmm, should they toss that money right out the window and tear that curbing up? Seems like a lost oportunity cost at a minimum to you, it's at the very minimum going to be frustrating to the client.
I guess there are some people that like it, and it appeals to them. I guess I am one that doesn't like it, and it really does not appeal to me. I'm opinionated about certain things (just ask my bosses!

), and this is one of them.
If you want to do it, go right ahead. Do a search, there's been a few people that have asked about it in the last few months.
Think about this though: You will most likely make more money in the long-run by re-edging beds by hand every year than you will with this curbing....
Just my $.02 worth. Take it for what it cost you!

Dan