I just purchased a Rieser equipment hauler 20' 14k capacity, after a lengthy research period. I was, like everyone else, looking for a well built unit at the best price. I actually found prices on similar design and capacities very close but I would have to travel some distance to retrieve the trailer. Try to find a dealer that sells lots of trailers. This keeps the price as low as possible, generally, due to reduced costs associated with transportation from manufacturer to dealer. A dealer that sells plenty of trailers often get a free trailer or two a year from the manufacturer. The dealers who don't sell many pay more to the manufacturer and pass that cost on to the buyer. I drove 180 miles to get the same trailer my local dealer has on its lot for $1400 cheaper!
My Reiser has the slipper suspension which is a solid design over some of the competition and 6" channel frame with 3" transverse beams at 24" OC. Lights are not LED but does have the 12k foot jack on the front with 2x8 PT decking and radial load E tires.
So, in a nut-shell, prices can be very subjective with respect to quality due to transportation costs to the dealer. Look for trailer qualities and design that best serve your specific application then look for the best price available.
Be careful with trailers in the 10-12k GVWR and make sure you compare apples to apples. Some come with slipper suspension and some don't. Some come with 6 lug tires some come with 8 lug. Others have 16" OC transverse supports and others are 24". I'm sure you get the picture. Good luck. I'm super pleased with my Reiser's quality and certainly the price too.
