I feel your pain.. I just went through this a year and a half ago.... I have found 4-star, Hart, Elite, Cimarron (NOT the same as CM),and Bloomer to be among the top tier of aluminum trailers. Sooner is somewhere between the top and second rung. Featherlite are considered good also.. I see a lot of Exiss out there as well. I think they are popular because they are lighter in weight and a littler cheaper, but the few I've put my hands on felt like tin cans to me (JMHO).  For a steel trailer I have looked at D&D over and over again, and think they make a pretty good product, but steel doesn't last long in my coastal climate.  My very first trailer was a composite (steel frame aluminum skin) CM. It served it's purpose well for 6 plus years, but in addition to the steel frame rusting, I had a lot of trouble with its "aluminum" skin rotting out. The escape doors, under manger tack doors, and lastly the back (horse) doors all were replaced at least once.. the escape doors twice.  I finally sold it and bought a 2H hart BP (aluminum) after I discovered the joys of camping. It took me 2 years before i was able to get right price, right size, right weight to fit my limits, best quality and most of the desired features all int the same trailer.  i will someday buy a nice light gooseneck, but haven't found the exact right one.. You have a greater advantage because you are starting out with a tow vehicle with a good bit of "oomph".. Good luck and enjoy the ride!.

Best wishes

JR's PAL,

I have included your post and answered some of your questions in a blue Font.

1. According to previous postings, there are many types of aluminum, not all are the best for trailer applications. Does Blue Ribbon Trailers use the best types of aluminum for horse trailers, including their BP? Blue Ribbon uses only prime billet 6005 alloy
2. Previous post about floors say use best materials are 125", heat treated to a T-6 and made of 5xxx series aluminum for better corrosion resistance. My quote from the Blue Ribbon dealer says "Floor- 2"x4" Aluminum I-Beams on 12" centers, full length extruded aluminum tongue and groove planks." Does Blue Ribbon Trailers use the recommended 125", heat treated to a T-6 and made of 5xxx series aluminum on floors? For both GN and BP? Blue Ribbon uses a 6005 alloy with a T-6 hardness for structural strength.  Our extruded floor had superior strength and durability over the flat sheet floor.  Flat sheet floors over the course of time will stretcha dn sag between cross memberfs causing moisture/urine to collect and corrode the floor.  We use the same floor on every bumper pull as we uses on our 40' 7 horse.
3. Previous post about trailer skin says most trailers with smooth skin siding is usually .040", and held on by tape. A better way is to use extruded siding which is usually .125" and is welded to each wall stud. My Blue Ribbon quote says "Sidewall Construction- 1.25 x 2.50 Aluminum Post on 20" Centers and 1.25 x 4 Posts at Dividers on Streetside with 0.50 Smooth Skin Side Sheets." Does this mean that the skin is thinner on the streetside? Or thicker near the posts and thinner between the posts? Do you think Blue Ribbon has adequate thickness and attachment of skin? Blue Ribbon's Skin is thicker than the .040 skin as well as a harder alloy which is a 3004 h291 full hard sheet.   This is the same sheet used by nationally known semi trailer manufacturers.
4. Mr. Trailer does he says the roof is one piece and every 3 inches, stainless screws attach the aluminum skin to the trailer coves and nose. I think that is good.
5. Mr. Trailer review of the Blue Ribbon Trailer seems to indicate great engineering (strong floors, mitered corners) excellent fit and finish (by Ohio welders who are used to close tolerances required on semis.) Would others agree?
6. Safety: Mr. Trailer review of Blue Ribbon seems to think they design and fabricate well (like the fact that any door that comes in contact with a horse is hand built with hinges welded on. There are 32 inches of welded hinges on the rear doors- more surfaces to weld on a miter joint.)
7. More Safety: Strength from continuous welds on boomerang gussets (whatever the heck that is.) Rounded corners on running boards to protect legs of tied horses.
8. More Safety: Mr. Trailer says Blue Ribbon uses Dexter torsion axles with 22 degrees up. The quote I got from a Blue Ribbon dealer says "Axles- EZ LUBE 3500# Rubber Torsion with Electric Brakes and Powder Coated Sub Assembly." Is this heavy duty with respect to my horse weights and trailer weight? The horses come in at 3000# total and it is very hard to find how much the Blue Ribbon SE20 weigh but a Colorado dealer lists it as 2640 pounds, so if that is correct we have 5640 pounds plus tack etc = about 6600 pounds. So the 2 axles at 3500 each should be just about right, am I getting this right? Everything you have stated here is correct - keep in mind that you also have weight transfer to the tow vehicle with between 10 and 15% of total evenly spaced load.
9. My 2008 Expedition can pull 9200 pounds with its heavy duty tow package. So that seems to have a margin of safety.

If you live near Columbus, now would be the time to go and look at trailers.  The Blue Ribbons are there and I thought they were nice.. lot of features that were really nice, such as the front bulk head on the slant comes out so you have the whole trailer to use as cargo, as well. 

Jbsny