While I wouldn't totally rule out a used TT, the fact is that you don't know for sure just how diligent the previous owner was in maintenance...regardless of what they say. New? Your chances are much better that you won't have issues, but if you do, there is time to remedy.
We purchased both our HTT and our TT new and were slightly better than the 30% discount. Both came from RVW. In doing online searches, we were able to compare like units and confirm that we were actually getting a good price. Suggest you spend some time online, check locally, and try not to let your heart overrule your good sense. It's easy to get emotionally attached to a trailer when it looks and feels just like the right one for you. And if you can't come to an agreement that suits you....agree to walk. They'll either call you or you continue your search. Back to online with the model and specs of your perfect trailer...it's out there, just sometimes takes time to find it.