Buy the unit that has the layout you prefer. You'll be happier longer. We bought a used TT that we liked and it was in good condition. But after several trips, we discovered there was NO comfortable place to sit and relax inside.
We just traded that TT in and purchased a new Open Range which has a couch and two recliners. A 'much' better floor plan for our life style.
Also, find a 'good' PDI (Pre-Delivery Inspection check list) I thought I new what to look at on a TT, but after reading several PDI's, I discovered several new things to inspect before purchase.
Final note. Not all dealers are made equal. Find a dealer that you trust and are comfortable with. Ask fellow campers in your area and do some on-line searches. I 'think' I got lucky and have found a dealer who will stand by his word. So far, so good.
Happy Trails