Have you been able to get into it and test it (ie, how does it compare to maptools, as far as stuff like macros, multiple die rolls, etc)? I registered on the site, tried to make a game to try and play around with it but kept getting errors when trying to create the game. And I only found 1 screenshot on their site (granted I wasn't looking intensely hard) so I'm not even sure how it would operate in action.
*edit - ok, found the sample game, I just didn't read the front page very much, just jumped to the FAQ which wasnt there and tried to find a screenshot.
So far, It seems very clunky interface-wise and underpowered compared to Maptools, specially the dice rolling, and the chat in general (which doesn't seem to scroll with the new text, although thats probably just a 'beta' thing), and I didn't see anywhere to do macros, or stuff like card decks (for savage worlds, or deck of many things, whatever) (although I was on 8 color VNC into a netbook with low resolution since it didn't work on my computer, so maybe i just didn't see it), but I dont think it brings enough to the table (no pun intended).
I could maybe see the fact that its web-based and a bit easier as a plus, but that also means your tied to their server as to whether it will work or not, and they could start charging whenever they wanted, so I'd probably even then still say that learning maptools and the extras that go with it (port forwarding, vent or skype, other tidbits) would be worth it. Course I could just be biased, and my first response to most things in life is hate first, so I guess you can just ignore my bitching, lol.