If there were ONE "highest quality" unit out there not many would buy anything else. I can only comment on brands I've owned and the Rockwood has been gold for me from day one. Had one warranty concern during the two year factory warranty (toilet valve had to be replaced) and that would have been under $50.00 had I paid for the repair. First concern of any consequence was replacing the converter on our way home from Alaska and with more than 50,000 towing mile on the trailer. Now with 80,000 plus miles it's still a VERY reliable trailer.
Here's a link to a web site that allows owners to rate their own RV based on a standard criteria. Take brands with low number of returns with a grain of salt whether they're HIGH or LOW. Good luck / Skip
http://www.rv-coach.com/RV/manufacturers/survey/rate_your_rv_results.html