Gee, I have it and love it - but I tend to forget I have it and grab my other border punches. It can be tricky to figure out the spacing, but there are some awesome youtube videos out there with hints - and once I have the spacing figured out for the punch, I write it on the bottom so I have it for the next time.
Here are links to the video - it's in 3 parts:
Video 1
Video 2a
Video 2b
I think my favorite thing about these punches is that you can combine them for custom borders. Also, all the tonic boot-style punches work with the border system, not just teal & grey ones. The corner guards on their corner punches remove easily in two pieces, so they aren't easy to break like the old-style EK Success/Stampin Up ones.
I did have one punch that I had trouble punching thru cardstock with, but I e-mailed Tonic customer service and they had a new one on its way to me in a day.