I've got a black edition and a ZS as well (my wife has the ZS)
I'll say the black edition is somewhat more "eager" to drive than the ZS, it seems to have a much quicker throttle response, and pulls more willingly when above 2. gear.
Do note however that the black edition has lower gear ratios, so it sits at rather high rpm at motorway speed. In Denmark the speed limit is 130 km/h (I think that corresponds to 80 mp/h) and I'm pretty sure the black edition sits around 3.500 rpm at that speed. Can't remember for certain because I rarely use the motorways.
MPG wise I hit around 40 in each, but we mostly do short trips of less than 10 miles, so that's why. It's still much better than the other cars we've owned (Toyota Aygo, Ford Ka, Honda Civic 1.8 to name a few)
So if you do a lot of motorway I'd take it for a test drive there, to see if you can live with the lower gearing. On any other road I'll say it's far superior to the ZS :-) (And I'm loving every minute in mine)
Edit: Haven't gotten around to put a picture of the black edition on my profile, so the blue one is the ZS :-)