I have both Modular , A g2 key and a G1 rack.
The G2 is a little more hi-fi sounding than the G1 but it is not more “soft sounding” or worse than the G1, just different.
I have made a comparaison of both Nord Modular playing approximately the same patch : https://soundcloud.com/sovietpop-1/nord-modular-g1-vs-nord-modular-g2-new-file
The G2 is still compatible with the latest version of Windows (10) and OSX (El capitan) so compatibility is not an issue and its going to be fine for a while.
For the G1 under OSX you can use Wine (works very well) or a virtual machine.
Back to the G2.
Its a Wonderfull instrument, everything is well thought , the workflow is superbe and the interface is a work of genius imo.
The G2 is one of the most powerful and deep hardware synths ever created.
I have made custom sequencer with it to sequence my other gears when playing live. I have made some weird digital fx , synth etc.
Its a performer instrument, you can even sequence different variations of the same patch , crazy stuff.
Personally i would not buy the Engine version because you are missing too much. Get the G2 key or a second hand G1.