I chose a slightly more expensive model to get a thicker/taller frame and stringers that are closer together and not just because it had the torsion axles I wanted. I could have bought a lighter 7000 lb trailer that would have been marginal for what I carry, but I doubt it would have held up as well as the model I selected. I put 6-8K miles on mine each year while loaded at 6-8k lbs. I had also heard of the less expensive trailers made in the southern states and how some of them actually have shimmy and shake as you tow them.
Next Spring, I will be replacing the tires for the second time which means I am averaging about 4 years and 30k miles on one set. The last time, I upgraded the LRD ST225/75R15 tires to LRE hoping to get a little more wear life out them, but they look like they will last about same - At least I didn't pay much more for the higher rating. I'm considering looking for a 15" LT tire that might fit but am not sure if going 6-lug 16" rims and tires would work out financially with any better tire longevity.