Which 7 do you have or are looking at? I owned a TQ, good buggy for beginners. Parts are cheap and the car is reasonably strong. Check whether your LHS stocks all the parts.
If you go with the TQ RTR, there is a few things you'll need to upgrade. The stock servos are bad, really bad, replace them. The steering knuckles of the front are a bit weak in the threads, you'll get a bit of use out of them but they will break sometime if you race it. There are CNC steel knuckles that are far better. I also replaced the front CV driveshafts with the uni joint versions. They were far stronger.
I personally liked my 7 and if you just wanna get out there and get racing, it's a good car. It will struggle against some of the newer cars, but it's still reasonable.
It's mine: http://au.youtube.com/watch?v=usYhSWbmx6s