The slide out is a big mechanical contraption that weighs a few hundred pounds. It is subjected to weather, load transfers, and it needs to operate under all conditions or elevations. Most owners have never looked under their slide out or done one thing to maintain them. There are a very small percentage of slide out problems with a lot of them relating to the electrical side of things.
Given the amount of passengers that will be using your RV, I'd suggest to get one with a slide out. It will rain when you're camping. Everyone will be inside at some point. At that time, you will very much enjoy the slide out.
Dutchmen has some good points, the one of usability when slides are retracted is a good one. make sure the bathroom, at least, is available when slides are in.