Socal has some of the older players? Have you ever played badminton in Socal? There are great players everywhere...Socal has plenty of players as well such as Hock Lai Lee, and some im sure you've never heard of but are of national caliber as well.
Let's not turn this into a NorCal vs. SoCal thread. I'm from NorCal, but I live in Socal currently, and they both have great players to play with/against, but that wasn't part of the OP's question. He asked for the general overview regarding clubs, and that information has been given. As for coaches, it really depends on what you're looking for. In NorCal, if your focus is doubles, you should probably train with Chandra. If your focus is singles, you're better off with Holvy @ Smash City or Minh @ Bintang. If you don't have a focus, and just want to get better, pretty much any coach at any club can do that for you. I'm not too sure about the SoCal coaches, though I'd guess that the coaches at ABC and SGVBC (I'm thinking Hock & Johannah) are more singles-oriented. Again though, any of the coaches will be able to help you improve, and subtle distinctions like focus don't really apply unless you're actively looking to specialize in a single event.
I don't know why he's leaving but it's probably something along those lines. Cause ya... like all the coaches left and there's only 2 left at GGBC 2. It's really sad cause there used to be a lot more.
I don't know why people left either. Possibly like someone once said - that Mike is selling GGBC. People don't want to deal with uncertainty? Perhaps badminton business is expanding too rapidly, somewhat reminiscent of the dot.bomb era? And GGBC has reduction in revenue that can only be matched with reduction in personnel? I'd been coached by Mike for a year quite a few years back. I didn't get the impression that he's a mean person. Ambitious (with his ideal, of setting up a high-quality gym), yet approachable.