You really need to consider the kind of traveling you want to do and where you want to stay.
As noted above, if you don't have a 'dinghy' or 'tow'd', you're stuck driving the RV anywhere you want to go, which is less than ideal. Class B's are smaller, but can still be a pain due to height and maneuverability... and the're usually on the short end of towing capability. They also have very limited interior space.
For what you would pay for a nice Class B, you can probably get a lot more for your money in Class A or C.
One issue with all of the above is that it's a separate vehicle that must be registered, insured, maintained and stored. And it's not very useful for anything but being an RV.
A truck/ 5th wheel trailer IMHO makes a more versatile platform. The 5'er is going to be as roomy as any Class A, and you also have a truck that can be used for getting around once camp is set up, and it's still a truck when the RV trailer isn't in use.
There's also truck campers, which is what we have. For us, it met a specific need (we need to pull a car trailer), and it's pretty versatile, though not as roomy as a Class A or C.
For most people, the truck/5th wheel combo presents the best value.
As noted, get enough truck. You can never have too much truck.
