Count me as being among the Softube fans. But IMHO their best work to date has been the plugs they did for Native Instruments: the Vintage compressors and the Premium Tube series. Those things are amazingly good, particularly the comps. Don't let the Guitar Rig requirement dissuade you from trying the Vintage line -- they're well worth the extra bit of work to set up.
Back on topic: I'll be demoing the new Slate compressor as soon as I can, but as with anything, it'll have to give me something I need and can't get elsewhere for me to buy it. That turns out to be true of very few plugins, in my experience.
Anyway, these are good times for ITB music production -- the way things are going with HW power and advances in modeling, pretty soon nobody will be able to tell which recordings were done with studio-quality desks and outboard gear, and which were done by hobbyists on their computers. At least, that's my theory. Time will tell.
Cheers,
Eddie