In my experience, the SSL channel compressors are a bit thinner sounding than the bus compressor on full program material. Feed forward vs feed back - the bus compressor is a little more relaxed and thicker, the channel comps excel at shaping individual elements. I personally believe all the console 1 compressors are better suited towards individual elements than busses. I'll tell you what might be worth checking out as an alternative to Waves, the TDR Kotelnikov. It's a fantastic, transparent, and intelligent compressor. Doesn't dull the audio, or kill the highs, which is very desirable in a bus compressor.