Thoughts:
+ Colours on this trailer are certainly better than on Ult OP. The latter is gray whereas this is silver with the blue lines on the top and bottom. Ult OP's trailer's Autobot logos are fully red, which looks as bad as the early Armada logos, whereas the Deluxe Trailer's logo is a "proper" looking tampograph - i.e. red where it should be, and not where it shouldn't.Only complaint is that the logo only appears on the left side of the trailer - for some weird reason there's no logo on the right hand side.
+ Overall the colours on the cab robot are quite nice. The Hasbro grey from the original version are gone, replaced with a nicer darker grey. The windows are transparent blue instead of clear, which helps to make the toy more distinct but isn't really much better or worse than the original (it's a matter of personal taste/preference). The overall paint appwork itself is better on this toy, not as sloppy as on the original. It looks a lot nicer than on the stock photo -- see griffin's 'in hand' photo in post 1 for a more accurate image of what the toy looks like IRL.However there's less paint apps on the vehicle mode. The hubcaps are unpainted (whereas they're silver on the original) and the yellow/orange airbrushing on the original is absent on this version.
+ The trailer itself doesn't do much more than what you see in pics. It's basically a storage container for other toys, and by no means a battle platform (for that reason, I'm keeping my Cyberverse Optimus Prime). It can hold up to three Legends/Legion Class cars - I currently have my 3 Legion Class Wreckers inside the trailer.
Should hold 2 Scouts I reckon... haven't tried yet. The trailer also has two "legs" which support the trailer when not attached to the cab (so it doesn't flop down) - but doesn't tuck away either. It's high enough not to interfere with the trailer's ability to be towed - but is simply there to stop the front end from flopping down when Prime's not attached.
Overall this toy is much better value than Ultimate Optimus Prime... I wish they'd released (or at least announced) this toy a whole lot sooner. (-_-) I still see Ultimate OPs shelfwarming, including in the Target where I bought my Movie Trilogy Optimus Prime... so I can't imagine anyone wanting to by an Ultimate OP now with this cheaper alternative (unless you prefer Prime to go all "Powermastah" and combine with his trailer).
+ The lack of any weapon is disappointing to say the least. No idea why they couldn't have included any of the previous weapons that came with this mould, especially given the rather rudimentary engineering with the trailer. Or heck, just a repaint of any 5mm weapon, even a non-mech tech one (as it would have less parts and would be cheaper to produce).
Overall a nice toy, but it might be more advisable to wait until this toy's on sale.