What advice to first time TT buyers? Airstream 27 footer...

Well, IMHO. Why not look at a folding/PUP trailer. You'll get nice big sleeping areas. More storage options. It will be more cost effective as you won't have to buy such a big TV.
I know from owning 3 RVs. It's a pain to have to move stuff every night to turn something into a bed. It's also tough to have a big dog, (or two) taking up all of the floor space.
Also, throw in the cost of insurance, maintenance and storage. You can get a brand new PUP(with warranty) for the cost of a used Airstream.