Thanks to bobndot for the summary. I agree with what was posted.
Yes, they are a gamble but as others have stated, so are other things. The more complicated your coach is, the more potential for trouble you will have. Automatic awnings and stabilizers are good examples.
Get a slide out? It all depends on what your style of "camping" is, how many people are involved and a ton of other issues. I have seen slideouts that provide more space and options to view those large screen televisions. Some even have faux fireplaces! If this is your style of camping then you need a slide out.
I had a 21ft. hybrid with a slideout. It was a very small slide in depth but yes, it really did open up the camper. I was amazed. These things really do give you way more space than you can imagine. The issue comes down to need versus want and how much are you willing to expend when problems arise? We had trouble with water infiltration on ours as well as a faulty electrical switch. I know that my water heater will fail at some time as will my furnace and refrigerator. I would venture that my slide out will fail before either of the others. And it did, by the way.