We've been doing it that way for a few years. We used to buy the software, and install it on the PC, and we eventually wound up with few years worth of Tax software software cluttering up our home..
(We had since sold the software, couldn't use it anymore)
Its the same stuff, and we like the fact that all in info is encrypted, and you only pay a flat fee for the E filing (either $20/$25 I can't remember)
I was worried at first that anyone can find our data, but it is all set up with user id, password, etc.
We didn't bother with the state version since it is pretty easy to do on our own.
You can log on anytime and get what you need or whatever.