attack and release are added.
There is a saturation knob instead of the dirt button on the normal one and there is a switch for varying degrees of it.
Compress now has has gentle, punch and slam modes (under the compress knob). These are like mini presets for the attack and release knobs... so pretty worthless.
Sidechain has a gain knob now as well.
There is a character knob that can be set to fat,warm or bright. Honestly if you don't go to hard with this it's nice.
And you can run it in stereo link, dual mono, or MS.
I don't think the original was based on the 1176. They mentioned some sort of tube compressor or that it's modeled on a tube compressor.
I don't think it would make much sense to have 2 1176 emulations (native instruments has an 1176 done by softube called the VC 76).