I'm not sure what the technical advantages vs disadvantages are of the two. But I can see where both would be applicable. This is all just guess-work though, please correct me if I'm wrong, thanks
Open back cabs bleed more sound around them, so the sound can seemingly fill the room up more evenly in all directions. So IMO a small club setting open back is the way to go because you can turn up a bit and not have to worry so much about bombarding the people right in front of you with such a directional sound like you'd get with a closed back.
Not saying open backs aren't usable in huge stages, open vs closed back changes the over-all feel of the amp as well, so it's more to taste than anything else IMO.
Closed backs though, I think can make recording easier. Since hardly any sound is going to be leaked out the back, most of the freq. will be coming out the front, so miking a closed back would potentially give you a fuller tone. I've actually heard of people who mike both the front and the back of open back amps, so I can't be too far off the dot on this one lol.
But still, there are great open back combos and closed back cabinets out there, all of them sound great, I don't think one is inherently -better- than the other, though in certain applications one may be more ideal.