Best bed edger for precision edging.

I'm looking at buying a bed edger. I own an echo redefined and it's worthless. I have tried a bed shaper a few years ago which was ok, but I didn't think it went deep enough, I also found it hard to clean an existing edge with it. My clients frequently tell us, they don't want the beds getting any wider and to follow the same line.

I was considering the turf teq. But wants sure about how precise it is? Cost is not a factor. I want the best unit