Cannot comment on either of the trailers......
Re: brakes - I would go electric over override.......I have had override on one trailer and it annoyed the hell out off me.
I skipped electric and went to electric over hydraulic for my current camper.
Re: hitch, never owned a poly block but have watch plenty struggle with them and the odd few that have it sorted. DO35 for me, cost a bit but easy to use.