Best Carpet for fit and finish, either way, it's going to be an ACC carpet, the ship flat (non rolled) carpet is an exclusive offering from Dave Walden at ECS, AFAIK he's only offering 80/20 loop as original, it'll run you about $300 with shipping

Other vendors can offer you an ACC carpet, but who knows how old, and how long it's been sitting in a box on the shelf rolled up?

Personally I prefer the look and feel of the HIGH CUT PILE carpet from ACC, so I custom order it either directly from ACC, or one of their distributors, being custom ordered means it's made to order, new, not laying around for years in a box,...plus IMHO the HIGH CUT PILE is far superior in finish and looks than the stock "grandma" 80/20 loop "rug," the HIGH CUT PILE will run about $300 +/- with shipping also