It depends what you’re going to use it for most, if you’re going to mainly be transporting Land Rovers over a decent distance (for me anything over 30-40 miles) then a decent sized transporter trailer would be best. No point in getting something so universal it’s carp at all jobs.
I started with a 16foot dropside tandem but it was a pain in the arse to load, pain in the arse to strap vehicles to and didn’t necessarily feel the safest or the most relaxing to tow. After considering what my main requirements actually are I’ve since swapped to an 18ft Bateson tilt bed tri axle and it’s the best thing I’ve done. It’s happy at speed and max weight, and is a lot easier to strap vehicles to. Ironically I’ve not struggled without the dropsides, you just learn to get good with the straps!
Tri axles for me give a bit of extra reassurance if a tyre were to go especially when loaded right up, but they do like to push the tow vehicle around a bit in corners so a decent sized tow vehicle comes in handy. Just 6 sets of everything to replace unfortunately.