I replaced Buffermount with NTMT when I could no longer source it easily. NTMT is made by D&K Coatings who bought out Seal/Beinfang. I can't remember if I could tell a difference when I first switched over , but I think they are practically the same. In fact, I may like it even better. It is certainly offered at a much better price. I buy it from this place: http://artgrafix.com/store/page151.html
I switched to this
and gave away my dry mount press. It has a completely different set of tradeoffs. It's pretty easy and requires no heat. I found it more reliable than a dry mount because it's not easily going to let go which of course means you are not going to easily separate the print from the board later. If never found any definite info on how archival it is but I've been using it for about 5 years. It will work up to about a 20x24, beyond that and the paper may wrinkle as the humidity changes.