A popular paint among the GB crowd is Interlux Toplac. It goes on smoother than Brightside and has a higher gloss. A consideration is that (according to the Interlux website) Toplac is not recommended for high wear areas. For that they recommend Brightside, which is supposed to be tougher.
We've been refinishing and rebuilding all the windows on our boat over the last bunch of years, starting with the aft head window which we rebuilt in 1999. With one or two exceptions when we tried Toplac, we've used Brightside on all the frames including that first one. The frame on the window we did in 1999 looks pretty much today like the frame we refinished last year. We've not experienced any chalking at all. It's a wood frame so after stripping off all the old paint we painted it with multiple coats of CPES, then primer, then two coats of Brightside. It's not needed or received any touch up coats.
The longevity of the paint may depend to a degree on the climate, too. Up here, we've had no issues with paint deterioration on anything we've painted with Brightside or Toplac.