It's one thing for a developer to state their policy, compatibility and state when they will offer full support is one thing–but to actually advocate users defer upgrading to a new version is out of line. This is bad juju on Nik's part...and won't endear them to either their users nor Adobe.
I must say I'm disappointed with Nik. Many other developers (OnOne, Topaz, Imagenomic etc) have already released updates compatible with 64-bit CS5 on Mac, but Nik says that Viveza will be available only mid-summer and other products at unspecified dates after that. I love Silver Efex, but to my mind this is too long a wait.
Speaking of Mac 64-bit compatibility, any update regarding Photokit Sharpener?