The problem here is that there is no single bag that can do everything for MMA.
Bag one looks like a good all rounder, it looks nice and long, so you can practice low, mid and high striking. Bag 2 looks nicely shaped for clinching and kneeing, but is not long enough to practice low kicks on, which are something you will definitely want to practice.
Bag 2 will not be suitable as a grappling dummy, and bag 1 is not ideal either, but will be better than bag 2. The best option I would say, would be to get a bag like bag 1, its a good all rounder, and you can practice a full arsenal of strikes on it, even if its not the ideal shape for knees, it will work. If you could later buy a grappling dummy for practising your GnP too that would be a good route to go down.
I'm going to get one of these some time. Since Im a Thai boxer, I don't need to worry about grappling dummies, and this imo, is the single best thing for striking practice, since they look and feel so realistic BOB bag