I bought some of them.
They seem kind of expensive for something you can only use with the SONAR Producer dongle.
Heck they don't even work in SONAR Studio or Essential.
There's better.
There's cheaper.
There's cheaper and better.
Most of the alternatives come with real value. e.g. you may use them in the other DAWs you need now that we have all learned that we need several DAWs to get a full spectrum of functionality.
Most of the people who have bought, downloaded, and use the Pro Channel stuff got their goodies for $10 a pop... which ought to leave you with some sense of how valuable a set of dongled and crippled VST efx is worth these days.
You can buy em and try em, or consider some great alternatives. Some of the alternative actually have demos that you may try.
best regards,
mike