Congrats on the purchase but, why are your parting with the Phoenix? Just curious about it...
The Phoenix is a great mastering compressor - I've really enjoyed using it on electronica and some recent Ministry of Sound dance stuff, but it is not as subtle as the Knif: we also do a lot of jazz here (more and more) and the Phoenix is often just a tad too `thick' for e.g. acoustic bass.
The Knif way with valves, and the amorphous core transformers are very clean and open, in quite a unique way - I've been hooked on this sound since getting the Knif EQ over a year ago and now I want it in the compressor too. IF I need both, I'll keep both, but I think the Knif can do `thick' enough, as well as the clean.
(Actually, `clean' is probably the wrong word for the Knif as it is not un-textured: if I want clean, clean, I use the Sonoris mastering compressor which is just superb at invisible control. I don't really know how to describe the Knif signature really. Expensive and Addictive might do to start though ...)
Cheers,
Eric