i find .mac very useful and handy.
the only cons i find is the price and the GB... i have 1GB for my account, but i wish 1-2GB would be incl. in the $100 anual fee...
i use 90% of the features, and the homepage feature could be a little more advanced in features for building the main menu. also the bandwith once content is up could be better, people report to me that they get 100-200kbit dl speeds, but most have 3mbit dsl lines that support 375mbit dl speeds, so there still room for improvement...
What's Wrong With .Mac and How to Fix It