I also drymount and use the Seal Buffermount. I have also read a number of threads here and photonet about this subject. Some pro drymount some con.
If you are making larger prints, 16x20 and up, simply taping the corners does not make a great presentation. The middle of the print often bags and warps out and doesn't look too professional. Perhaps with small prints it is fine.
As for the archival part. I have not seen prints drymounted for 50 years or so to make an educated guess. I drymounted color for 20 years or so but they all faded to some degree, because that's just the beauty of color, (thanks Kodak).
As for black and white, I selenium tone, drymount with archival materials and hope for the best.