I fought the same myself as I went from a single bike (Dyna) to a second bike for my wife (1200 Sportster Custom). I had a good 5x8 trailer but wanted a 2 bike trailer. (Before the flames, I travel a lot in US teaching 3 week classes and 1 & 2 week TDYs for military...so uniforms & equipment with bike in trailer of no bike time).
I bought a Wells Cargo 7 x 10 (SE series).
Reasons; SINGLE axle...the most important to me because I can still move it easy by hand with tonque caster wheel. Not easy with twin axle. 7ft width lets 2 bike offset side by side. Only 10 ft lenght works. Biggest 1 axle I found.
Also, it had ramp door with enough height to get bikes in & out with windshields on. Check your height and door opening.
Has standard electric brakes, side vents (keeps inside cooler), low frame height, side door, LED outside lamps, inside lights, 205/15 tires which are better than dinky ones on some, standard rear corner stablizers (for when vehilce not connected). After trying others, I went with Wheeldock mounting. $300 each but keeps bike real secure.
Now down side. Heavy and large trailer. Really makes my 2004 6cly Explorer work towing with 2 bikes. Of course I am running 265/70/17s on the Explorer which isn't a help. It is wider and taller than the tow vehicle. Just, and I mean just, fits on the 8ft x 12 foot concrete pad.
I bought in Champagne. Looks cleaner than black or white as it doesn't show dirt as much. I would not buy black again like first trailer. Way to hot.
Last, I would buy it again tomorrow. About twice the price of cheaper trailer, but worth it to me for quality. ($10 head/$10 helmet or $2,000 bike in $500 trailer??). Hope that helps.