I used one as my main phone for about a month and I really liked it. As a phone it's pretty bulky - getting a call when you're out and about can lead to a few strange looks
I like the size a lot, and one of the main reasons I used it was to see whether I really need a tablet as well as a smart phone. I can't really see myself walking around with a ten inch tablet, but I could fit the 7.0 Tab into my pocket (just) and that makes it quite easy to carry. The app I use the most is Kindle, and I think the 7 inch form factor is perfect for that. Speed wise it is pretty good too, and the screen is bright and crisp.
I think the only thing that bothered me was that there's no way to get ICS on it at the moment (although rooting is very simple), and not much info on whether Samsung will be updating it any time soon.
I liked it, and if I get a tablet it will definitely be in that size range.