Well, if you are swayed to go with aluminum, then Mclain.. I have not heard many negatives on the aluminum sidefrom them, mainly the galvanized.
That said, if you want a truly nice aluminum trailer, then Rolls Trailers are bar-none the best you can get. All Aluminum, stainless hardware including hubs, custom oil lube like bearing buddy's but better and fasteners - you just won't get a better trailer!
Their Axles are what really set them apart (aside from the overall quality). They don't use springs and they don't use torsion axles, both of which can wear out. This fella was a rocket scientist/engineer brainiac type he developed these pivot pads. They have more travel, smoother ride and won't corrode at all. The developer had the design patented. He calls it a lifetime spring and is so sure, he backed them with a 100% lifetime warranty!
I have seen these in person and they are a fine piece of workmanship!
Check it out - they are only about 10-15% more than a standard trailer, but well worth it IMHO.