I got this last night and thought it was the most expensive $15 I spent on a 118KB file. And when I get getting the license expired or failed to authenticate messages, I thought I got screwed. The company's Twitter and Facebook messages were a bit encouraging, but still felt I had been had.
This morning, their servers seems to have stabilized, and I was finally able to test it out with my 4S. The speed is amazing. And it's so easy. Just launch the app, launch the Mac component, and I'm online instantly. The Mac component didn't crash on me. (MBA 2011 on 10.7.2) Speedtest was around 3 Mbps down. It certainly feels faster than the Internet at work. It may have been an expensive app, but it's worth it. Certainly better than paying an additional $20 PER MONTH to get AT&T's permission to tether. I would only need to tether when I'm not around Wi-Fi anyway, and that's rare.
Hope they do make good on their word to get rid of authentication. And Bluetooth tethering would be nice.