Welcome to iRV2. Just starting into RVing can be very confusing and down-right scary. Everyone has an opinion about something and everyone thinks that their brand is the best.
The best way to approach this is to look at some RVs and then rent one for a few days and hit the road. You will quickly find the things that do not work for you. Also, you need to make sure that you and your spouse can stand being together in a small space for an extended time.
Now you have an idea of what can work and what can not...look at new and used, but buy a used on for your first RV. Something 2, 3 or 4 years old will have suffered the depreciation and be much better to sell with minimal loss when you are ready to move up or down. With a used one, be sure and spend a couple of hundred dollars and get an independent, 3rd party inspector to check the RV and all of the systems before you sign the papers. make the contract contingent on your inspection and approval.
Next thing is to forget every thing the dealer or sales person tells you. He is not your friend and his job is to sell RVs. When it comes time for the contract, be sure that every little thing the salesperson has promised is included in written into the contract.
On the used ones, check - NADAguides.com Official Site
for the pricing. Use low retail with no options added as a realistic price in todays market. Offer 10 to 20% under that as a starting point. Make sure the dealer includes (not as an add on) a full Pre Delivery Inspection which will demonstrate how every thing on the RV works before you sign the papers and hand over the money.
DO NOTtake delivery of the unit until it is 100% and to your satisfaction. Once they have your money, dealers have a way of forgetting about the little things that need fixing.
Have fun shopping.