Been using the SSL plugs for quite some time now. They are great and serve a purpose. However I can't use them on everything. I go to them for that sound.
I love the API stuff too. They are very tight and thick sounding to me.
The SSL sounds a little thinner.
The SSL comp sounds good as a drum buss but I have other stuff I like better depending on the song.
Don't sleep on the Rcompressor or RVox or even the Ren Eq's
They are FANTASTIC and as plug ins go are every bit as good as the SSL stuff.
Just a different flavor! Each has their own mojo right for their specific occasion!