One valuable thing I learned is how little regulatory oversight there is over the RV industry. When you buy a car, you are pretty comfortable that it isn't going to fall apart around you.
With rvs you have to be a lot more careful. Underbuilt and overloaded rvs are a big problem. Another thing I learned was that you want an RV that doesn't have a million little things that go wrong with it resulting in many trips to the dealer to get it fixed. Therefore you want to be sure you research in detail any brand and model you are interested in buying.
Look for safety and reliability before cosmetic features.
Another issue is pricing. As mentioned on this thread a couple of times, the MSRP means less in the RV industry than it does in the auto industry. It is also hard to make sure you are comparing apples and oranges when you buy. What are the options? What is included? Many manufacturers seem to have a relatively low suggested price, but important things you want are options that cost extra. Also, if they separate out the options when they talk about the carrying capacity and weight of the vehicle these option items probably won't be included, leaving the impression the vehicle can carry more than it can.