I'll give another little plug for Head Case. Danny was kind enough to let me test it when it was still in development, and its unreal. So happy they've finally released a commercial version - don't even delay, just go and buy it!
Back to the OP - rain, I bought Slate's VCC when it first came out because, like you, the stuff I demoed it on sounded incredible. Bt after buying it I quickly discovered that its not what you want all the time. I was very surprised that I liked this plug, because I'm very skeptical of stuff like this, but as I said, I demoed it, and it sounded great so I bought it.
I think you just have to listen carefully with every new project and determine whether or not its what you want. Sometimes, it works on certain instruments even if it doesn't work on everything.
The danger with this type of plugin is that you just stick it on everything without thinking, almost as if you feel a need to get value for money! I've found if you listen carefully, VCC can be a great tool, but I think your default position should be to NOT use it - for me, I need to be convinced that something is actually improving my sound before I let it anywhere near my audio! It seems so many people record their tracks and then just go into auto pilot and start to throw plugins on everything just because 'that's what you do!'
Gain staging is VERY important when using this plug.
You mentioned the RC Tube emu - I absolutely hate it! I find it just masks and muddies up everything I try it on!
So I wouldn't give up on it rain, but if I were you, I'd adopt a 'I've got to hear an audible improvement in sound before I use this thing' mentality. Start every project assuming you're not going to use it.