Nebula-Perplexed

I recently picked up Nebula when it was on sale after reading the hype about it for years.  I own the Viridian and Silver plugins and have been pleased by those, but always heard the 3rd party Nebula libraries were better.

So I purchased the Cupwise C660, spent hours downloading it and going through the insane installation process and slapped it on a drum bus for some Ringo style drums.  To my surprise, I thought the old IK Fairchild emulation (not the latest one) that was one there before sounded better.

I found that if I messed with anything but the input and makeup controls things sounded worse.  Messing with the attack and release settings made things sound broken.

I was curious if I'm doing something wrong, or if I really just don't like it.

Any tips?