I've had a few of both. I find that the later wobble boxes are nearly trouble free. However, I have had some nightmarish problems with older wobble boxes. I had a YearRound brand wobble box on a series II 20' that was aluminum, I had trouble averaging an 8hr day without wobble box problems, it made me appreciate pitman's. I personally like the pitman on older heads simply because they are so much easier to fix if and when you do have problems, parts are much cheaper too.