What great questions. To answer your OSB question, we use just enough. The primary OSB is laminated into the floor. This insures the Big Country to have the most solid floor in the industry. No toungue and groove with seams that could squeak and come apart (which are generally plywood and heavier). OSB is designed to retain strength when moisture is present, even though we prevent moisture contact. Please keep in mind that the OSB is part of the laminated floor. The OSB is laminated directly to the framing and block foam insulation.
Big Country offers industry leading construction and insulation. Big Country and Landmark are built on the same production line. Both products offer laminated roof (huge insulation & usage story), and laminated floor (which we have mentioned). Both Big Country and Landmark offer the 6-layer 2" thick sidewalls. Both Big Country and Landmark offer the full end wall insulation (under the caps), along with slide room floor insulation. With regard to the primary construction "bones", both products are very similar. Big Country continues the solid laminated floor under the bath and bedroom deck. OR just used luan floor. There should be no question, which is better here, especially for extended use/full timing.
There are a plethora of reasons to own a Big Country over the OR. Color - the all new Big Country PEARL edition features high gloss sidewalls, and award winning graphics. Big Country gives the look of full body paint, without the cost. You will find a Big Country offers everything OR has to offer, PLUS Big Country offers hydraulic front jacks and a full 6 point hydro leveling. OR specializes in the 12v slow jacks that you will always have to crawl under and adjust, even if equipted with the JT strong arms (advertised as one touch, but you have to pull the pins from each jack - at least 6 touches). Big Country is solid. Big Country offers the wireless convience remote, controls the slides, jacks, awning, and exterior lights from the remote. So many more items to list.
Then there are the reasons to not consider an OR. Biggest of which is the cable slides. Cable slides are not bad (we do use on a few models), unless they are run over 24" slide depth. OR runs the slides 38" - 40" deep on most slides. We used to go to out in the OR and jump in the end of the slides. Trampoline effect - I would not reccomend if you own one. Big Country is solid.
To another comment on the post - Heartland started 10 years ago as an independent mfg. One of the biggest reasons Heartland was purchased by Thor was because of Heartland's product value. It was getting tougher and tougher for the other Thor companies to compete with Heartland's products! None of this has been lost today. Heartland is stronger than it has ever been, with increased emphasis on service to dealers/customers, more audit testing then ever before, and more product testing than any other RV manufacturer. Thor has brought better people to Heartland, while improving the exisiting employees.
There should be no question that the Big Country product leads the 5th wheel segment in product innovation, eye appeal, and most importantly - value. If you would ever want to discuss, please feel free to contact me personally on my cell: 574-532-1491. We love 5th wheels, and the people that use them. I will probably see you at a campground soon (after this silly weather leaves Indiana).
Happy travels - do it better in a Big Country!