I agree completely with Ron Dittmer. He has provided outstanding advice. Buy used to save the depreciation and buy the best construction you can afford. Yes you will have repair costs, but if you buy quality these costs will never be more than the hit you take buying new. Even new rigs have bugs that need to be worked out, but if money is not an issue, there is a strong case for buying new with a warranty.
I recently bought a 10 year old Coach House 272XL with the Ford E-450 chassis. I have a repair fund and since taking the rig on the road have found some items that need attention. Biggest item is the two slides. They work fine but some of the seals need repair or replacement before water starts getting in. This is normal as the seals are 10 years old. You will find that the slide seals are one of the trickiest parts of an RV for the manufacturers to get right. Just goes with the territory as you have an entire section moving in and out. Many people avoid slides for this very reason, but they are very nice to have to maximize space.
Beat source of impartial information can be found at www.rv.org. Kind of a Consumer Reports for RVs.
I looked at dozens of RVs over a period of two years and went for the quality. Happy hunting!