Hi Sergio,
VAT gets changed with a click - easy. I am talking about new functionality. They used to introduce new features twice a year. I read on their forum they've been busy developing browser based system, but no further info was available.
Updates and support are free... if you pay annual membership ;-). So they are not. How much you pay depends on the number of users. I think it is in the region of $250 for a single user.
The best source of info would be them, so get in touch if you are interested.
Good luck!