Any opinions on Dutchmen TT's

Make sure it operates smoothly across the entire range of travel in and out with no unusual sounds. Clunks, bangs, and cat-like sounds are bad. With the slide in, inspect the seals on the inside of the slide to ensure they are in good shape. Ensure the outside seals mate up completely on the outside of the unit (you're going to need a ladder). With the slide out, check the exposed seals for condition and check the other set to ensure they mate up completely.
With the slide out, check the floor for softness or other signs of water damage. Also check the header for any signs of water damage.