The concept is nice – keep track of your domains in terms of renewal dates and page rank, however it’s not that helpful if you deal with ccTLDs.
I added a couple of .com domains to it and it showed me the info from whois ie. expiration date and the page rank from both Google and Alexa. However when I added a .ie domain it couldn’t handle the renewal date at all.
While I can understand that it would focus on .com I get the impression that not much attention was paid to other ccTLDs apart from co.uk, which seems to work.
It doesn’t, for example, tell you which registrar the domains are with – regardless of their extension, so I can’t see it being that helpful for people using multiple registrars.
However if you only have a modest domain portfolio with a single registrar this might work out quite well for you… It’s free anyway, so you can’t really complain 🙂