My dad got one 10 years ago or so. Here's my experience:
Pros
Compact, easy to use, easy to tow
Most come with an A/C unit if you have power
Sleeps a family of 4-6
Cons
Even when fully supported, it does move when folks toss and turn
The matresses aren't the most comfortable
Will keep out the rain, but a big, soaking rain will find it's way in around the bed areas
We mainly use it to go camping at the river. My BIL and friend, plus myself, is all I can stand to stay in one. One on each pull out end and one on the table that folds into a bed. I really never sleep worth a damn due to a) they snore like bears and b) even when it's fully supported and anchored, my BIL can roll over on one end and it moves the unit just enough to wake me up. He complains about the same two issues. We have gotten pretty moist in them due big rain events. No leaks, but seepage around the edges of the matresses. As long as you can sleep in the middle of the bed (tough for me at 6'4"), you're good. I like them for they're portability and ease of use. Having taken them to places with power, the A/C is awesome and it works really well (as does the heater). It's also nice to have a sink and cooker. If you do get one, you'll enjoy it. Store it under a shed, though. No need to have the elements reduce it's life. Open it every couple of months on a nice day and let it air out. Take care of it and it'll last a long time and you'll have many good time with the kids. Surely beats sleeping on the ground!
He has a Coleman like the one below:
Enjoy!