If you camp a lot and have done your research and given it serious thought I think buying new is fine. In the end all the layouts are pretty similar and the advantages of buying new is you get exactly what you want. Buying used could bring a whole host of other problems depending on age. Buying used does have its advantages also but in the end it’s up to you. I have always bought new and have never regretted it. I bought our first TT for 19k and sold it 7 years later for 12k with over 400 nights in it i felt I got my $$$ worth.
Don’t buy any of the extras they offer at the dealer. Warranties, coatings and host of other things. You will need a battery, cord if not attached, propane and a sewer hose which should come either the rig. You will also need levelers, I like Anderson levelers. Don’t buy to much at the dealer without checking on amazon first and make sure you research online for the cheapest price you cand find the rig and offer less then that. 35% I think is the rule of thumb off Msrp. If you pay to much and finance in all the extras then you will be screwed and buying used probably would of been a better option.