Combs has more roles:
-Weyoun (multiple DS9 eps)
-Liqudator Brunt (ditto)
-That Ferengi on the Enterprise Ferengi episode last season.
-He played some alien that wanted Quark to make a holosuite fantasy about Kira (don't remember that character's name).
-Shran (three Enterprise episodes).
Plakson has only 4 so far:
-Dr. Selar (one TNG episode).
-K'Ehleyr (two TNG episodes).
-The female Q (one two-part Voyager episode).
-and the Andorian character in this episode of Enterprise.
So Combs has gotten more airtime, and played more roles, but Plakson has been playing in Star Trek longer, and been on 3 of 5 seires as opposed to Comb's 2 of 5. That is unless I'm missing some data from Voyager
Also I kind of like the irony in this episode -- Plakson's character in this episode is an Andorian who hates Vulcans, yet her very first role in Star Trek was a Vulcan!