I agree with John on all of his points, and will add a few of my own. If you enjoy camping out of your vehicle, a RTT is AWESOME. Period. I have the model that you linked to, although it has a different name, they all come out of the same manufacturing plant. I bought the RTT, changing room, and awning all in one swoop, and got a heck of a deal on it (about 750 bucks for all of it, but I picked it up from the distributor here in Europe.)
If you will be staying in the same place for more than one day, like the concerts you mentioned, you should definitely spring for the changing room. It is worth every penny, especially if you will have your spouse or kids with you. Although, its a bit unneccesary for only an overnight stay.
I agree with John about the awning as well, they are worth their weight in gold when the weather gets nasty (either rain or sunlight), its nice to have a place to stay dry and do your cooking under, or just for lounging around.
On my last trip, I had heavy rain all night long, and was completely dry inside. The are very nice tents, and not made of your typical thin tent material. Like John said, you will want to keep the door/window awnings down during heavy rains as it will help keep everything dry inside. Last year, I was camping on a lake in Sweden, and we had at least 40 mph winds. The tent was just fine, and I had zero issues, even with the door/window awnings up. These things are tough.
There is plenty of room inside as well. I am 6'1" and 300 pounds, my wife is 5 nothing, 125 lbs, and we have no issues. It is the same exact width as a queen size mattress, but it is 15 inches longer. We usually put our clothes bags down at the foot of the tent, and still have plenty of room to strech out. As far as comfort, compared to a regular tent you will sleep like a baby. The included 3 inch mattress is quite comfy. I can comfortably sit up in the tent, and I spent a lot of time in the tent on the last trip watching movies on the laptop. My wife can sit up on her knees, which makes changing clothes easier.
There is definitely an added sense of security being up high on your roof, but as John mentioned, you should keep valuables locked away. Also, we are able to leave both our sleeping bags and pillows inside with the tent folded up, which will free up space inside your jeep for other stuff.
The only thing I had to "do" to the tent was add an indside light. I added a rougly 3 foot long LED strip on one of the inside ceiling supports, and it just plugs into my jeep cigarrette lighter outlets that I wired 12volts constant.
Bottom line, it is easily one of the best purchases I have made for my jeep/camping, and worth every penny. I make it a point to use mine atleast once a month though...
Here are a few pics,
Ladder side:
Opposite side and awning:
Changing room on my old truck:
Folded up for travel:
Let me know if you have any more questions or want more pics.
~James