Hmm. Some Exclusives are passes for me, but some others may want them because they DO know more of the background history. I may not know the background on the history of the cosmic cube, but by reading up on it, i'd prolly figure what some already knew about the battle and want it afterwards.
But if i missed out because i didn't check my email, or if the server(s) were down, then that's just one way of saying, i missed out. if i really wanted it, i'd make an effort on the second market.
I missed out on the stealth iron man. Luckily, i have the regular version and can almost deal without one.
As for exclusives and what Shai said, I agree. Yeah, I can possibly get it for at least $50 less elsewhere shipped, but I've come to like all of the Sideshow staff I've gotten to converse, etc with, and it's our money that helps them out too.
Way I see it, the more money you feed back to the source, maybe they will have more money for R&D. More R&D may help get you different exclusive add-on's... who knows.
But as another rule of thumb, the exclusives were meant to add an additional detail to the character not really seen in all of the character's story, just a snapshot, such as Leia's blaster vs pistol, Vader's mini robot thing, Doom's Pimp Cup (which I think is one of the best exclusives just cuz it looks frickin cool), down to Spidey's camera.