I don't think prices will drop any further, so from that standpoint now is the time to buy. I personally think they will start going up in the near future, especially if the next code update is a homerun. But who knows? I don't care either way...I have mine and it's not going anywhere.
I don't think we'll see another "flood" of X-Men hit the market when Star Trek or Metallica hits. There will be a few more for sale, no doubt, but we already saw the big flood when Avengers hit (and it was bigger than usual because of the software and hardware issues). Avengers is next in line to flood the market. That's just how it works. Every time a new pin comes out, the last one sees a big sell-off by the early adopters. There are a few exceptions, but that's almost always what happens. Then a few months/years later the machines will have found there way into more steady/permanent homes and the prices will stablize or go up as less people will be selling at once. It happened to Spiderman, LOTR, BDK, etc. Even IM and Tron (in pretty huge ways too). It will happen with Avengers, Metallica, and Star Trek. It's definitely going to happen with WOZ...and that's going to be a HUGE flood I think (for various reasons...none of which have anything to do with the quality of the game).
So yea...that's a lot of words to say yes...now is the time to buy X-Men.