There are a few things I want when looking for a trailer.
Flat deck - I want the deck to be above the tires. This makes it very convenient to fork pallets on and off and allows you to put the forked load over the axles
Pintel hook - I prefer the pintel hook when I'm by myself. This allows you to back into the hook without doing damage to the vehicle. You stop when you gently bump the hook. Perfect every time.
Extra capacity - Always buy a trailer with more capacity than you think you will ever need. This prevents you from outgrowing it for at least a couple extra weeks.
An appropriate tailgate or ramps - I like both tailgates and ramps. Having one of each, I can definitely say the tailgate is better. The only thing the ramps are better on is incredibly uneven ground.
Tires - "Tires wins a race"
] I want big over sized tires. I want truck tires. I don't want little Yugo tires, I don't want car tires, I want real tires. I wont even buy a boat trailer unless it has truck tires. Small tires suck.
Keep in mind what you will be towing with. A well built and balanced trailer will be easier on your tow vehicle and worth the extra money in the long run.