Here's my op-ed in the Week on the hurdles facing a recall of Governor Chris Christie. The article runs through most of the challenges, including the massive amount of signatures needed (significantly more than were needed against California Governor Gray Davis). New Jersey's law has a very high signature threshold (25% of registered voters), which has resulted in very few recalls in the state.
One point that I briefly touch on is that I suspect that New Jersey may a stricter standard on signatures than other states (Wisconsin's law is arguably the easiest -- it allows all eligible voters to sign, signers don't have to be registered). In the past, I've noticed that certain states (Arizona, Colorado) seem to throw out signatures with a higher frequency than others. If you scroll down one article, you will see a high profile petition in West New York (it is a town in NJ) that had 40%+ signatures tossed out. That is a very bad sign for a Christie attempt -- if that is any indication, petitioners would be looking at needing over 2 million signatures just to get on the ballot.