I might be the only one not completely frustrated by the line and still collecting.
Batman was and is my favorite DC character. That said, Mattel is doing goofy MOTU style things to this line. A single quasi-chase figure per series (Robin, Joker, Croc, Freeze) can make it frustrating. Worse, after losing patience and paying too much, the good figures start showing up in two packs. Robin (red version) has become available in a two pack with a Batman (can't remember whether it's the Zipline or blue version, both of which I have). So if you still need and want Robin, now you have to buy another Batman figure with it, one you might already have
Joker too is available in a two pack, but with one of those weird, purple deluxe Batman figures. Blech.
I got the blue Batman with the Superman figure. I do not like the deluxe or over-accessorized figures, though I am tempted by the white/arctic batman from the freeze wave. It just looks...different
I've had tremendously good luck with this line and I really don't think it's a) going to last b) quite as hard to find stuff, in most cases. I've returned several Jokers and Robins back to stores because I simply couldn't trade them and would take a loss on ebay. If I had the patience and held them, I could have probably made it worth my while. I've got a green Robin in the trunk of my car that is likely destined for a return at Walmart any day now. I've left at least three Killer Croc's on the pegs as well. I've only ever seen one Freeze though and it was the chase version. My regular version I got from a Canadian buddy out west. But the Freeze wave is very uncommon here thus far, so I'm fairly (over) confident I'll find more.
Probably my biggest disappointment with the line is that there aren't enough villains and those that do appear are not the ones I had been hoping for. Mostly because I'm more a fan of the comics than the movies or animated series I suppose. Killer Croc and Freeze are fine, but I was hoping for the classics. Two-face, Catwoman, Penguin, Riddler, Bane, Scarecrow, etc.
I just don't expect the line to last long enough to produce all of those figures. I would dearly love to have a well done catwoman figure, but I suppose time will tell.