My understanding is that open vs closed comb is mostly a case of "your mileage may vary" - it depends on you and your face. Large numbers of people swear by each. I am very much an open comb fan, for the record.
The only other difference is that in theory the gaps between the teeth of an open comb may be a better design for leaving lather for the blade and for cutting longer hairs. I have no clue if this is really true or not.
I used to consider myself a "why would I ever even consider a vintage razor?!" person until I tried the Gillettte New. Now I am simply refining which slightly different Gillette New open comb is the one for me.
BOTOC, GNU, LEMS, SERLover, Stirling Syndicate
New Shaver Guide - http://badgerandblade.com/vb/showthread.php/373872-My-short-and-somewhat-misleading-shaving-guide-for-those-foolish-enough-to-listen