This has been a very long update cycle; it's been about 5 months since 4.2.0! I guess that that means that 4.2.0 is pretty good. We've added an IJS driver and an OS X port; other than that, it's basically just bug fixes.
It's not going to be that easy to maintain 4.2, with some of the new printers coming out (Epson's releasing a 7-color printer; the 4.2 code has no really clean way to support a light black ink). Besides which, 4.3 has Even Tone screening. Mark Tomlinson has been hacking on it. He's finally cleaned up the bulk of the waterfall problem, and the quality is really, really impressive. The API actually hasn't changed yet, so we might actually want to consider using the mainline as the base for 4.2.2. Definitely something to chew on...