Strange!
When I bought my first Vietnampeg VR, I was going to get the 810. I went to the store where they had the Vietnampeg but they also had a Heritage and a NOS tweed Peavey 810TVX. I a-b-c'd them, and thought the Heritage was a very distant third. Much less efficient, wooly, woofy, and no upper mid bark. The Heritage I guess might have been a bit boxy, but that translated for me to more mid presence which I love. However, the Peavey killed them both (as long as the tweeter was off, yuk)...especially in build quality. It looked like a piece of living room furniture, and was a straight back design. The volume difference was astounding but with a very aggressive midrange. It was well rounded but not wooly or farty. It is a ported cab. I never DID buy an Ampeg 810! I've bought more heads, and two PF-115LF cabs, but I find their 810s are the worst I've ever encountered. I have 810s from Marshall, Mesa, Peavey, Orange, and Fender. The Ampegs just seemed cheap and sounded so...the cheap tolex and horrible loose grilles just turned me off even if they DID sound good. But, I DID prefer the Vietnampeg to the Heritage.