Bought the Metropolis Showdown set, probably one of the better value seeming 11.99 hero sets. Certainly FEELS like there's more pieces. Though I suppose if it's minifigs you're after it's probably of less value to someone getting literally any other MOS set, since this seems to be the same Supes and Zod in every set, besides the lack of Zod armour. For me, however, someone only interested in getting Supes and Zod cheaply, it's pretty good.
I actually like the car slightly less than I anticipated. It looked great in the promos, but in person it feels a tad unfinished around the doors, lots of visible studs that seem a little too exposed. The additional scenery is not bad though, a neat car flipping, tower toppling feature built in, and the car has a handle on each side for "holding" by Zod or Supes (by which I mean, you hold the car and clip the fig on for the illusion of holding :P)
I think it's probably about the same as Iron Man vs Mandarin really, I actually feel, goofy turret aside, that Mandarin's buggy is a lot more solid design wise than the somewhat unfinished car, plus IM vs Mandarin gives you two exclusive variants which this set doesn't. Viewed as individual sets however, ignoring what's available elsewhere in the line, I'd say this is the superior set.