I got both - the smart cover and the smart case for two different iPads. If I had to break down a pro's/con's for both, it'd probably be this:
Smart Cover Pro's:
Substantially Cheaper
Feels nicer
Doesn't add much weight to an already light device
Cons:
Having to be careful how you rest the iPad. I don't want to scratch up the back, so I've resorted to just laying it down on it's face (cover side down) to keep it from scratching.
Smart Case Pro's:
Protects both sides of the device
(I honestly can't think of anything else).
Cons:
Costs twice as much
Does put some heft onto the device itself
I prefer the smart cover. The only reason why I didn't get the smart case was because the black smart cases were all sold out. Disappointment, was convinced I would return the smart cover and get a smart case when they got back in stock.. Now? I'm not so sure. I loooove the smart cover. I think my only complaint is that it does leave the back uncovered. Having to flip it so it rests on the screen (covered by the cover, of course) to set it down is an annoyance, but not overly so.
With the Smart Cover does it only fold one way and can be upright or typing position?