I thought I would give my two cents.. After owning a 2008 Bighorn 3670, and now a 2010 Landmark Grandcanyon. I can honestly tell you what I think the biggest benefit to the Landmark is.
Goodyear Tires. Enough said there.
Hydraulic Landing gear is great...
The half body paint is nice, only to the point when you have to have work done. And they cannot match the paint up exactly. (has happend twice), Or you get a scratch in the paint..
Padded ceiling is nice.
I think the fluorescent lighting is terrible. Up here in the northland, when it is cool, it takes the lights 10 minutes to burn bright. We had a 2005 Everest 366i with the halogen lighting, that was the best. If we keep this unit, I am gonna look into changing them all out.
As far as I can tell the difference between the carpeting is nonexistant.
The Landmark pulls much easier than the Bighorn.
The 40# lp tanks are nice, especially when you have the Onan lp generator like I do.
The bigger TV is nice. The surround sound is ok.. I did replace the surround system in the Bighorn, to something much better than both.
With that all being said,, would I buy another Landmark? Probably not. Just not enough frills to justify the cost. I hear the 2011 will have auto leveling, that would be something I would look at.
again just my thoughts after spending time in both units...
p.s. With the Bighorn we had zero problems, with the Landmark, it has been many, but nothing major. Except the slam door problem.