The commentators so far are referring to the excellent advantages of
the wet
pump for IFR.

Far as I know, none of the separators work very well with negative Gs.
I have
a wet pump and the Walker (airwolf now) and if I do a 0 G parabaloa, I
get oil all over the belly.

If you are doing both acro and ifr, the dry pump might be better.
Bill Hale Loveland CO