I have seen a few of the developers here using 4.02 on their sites.

I believe that Scott Shecter - http://www.scottschecter.net upgraded his site to 4.02 last weekend and was happy with the result.

Since you're obviously experienced developers, then the latest builds would most likely suit you since issues that may require tweaking or fixing would be well within your scope.

Each version has it's own sets of fixes and enhancements, so downloading a couple and running some tests in your own environment would probably give you the best answers. 

It would be nice to have a crystal ball and be able to envisage the best for each individual, but with the 4 releases, I hear good and bad for both, so have come to the conclusion it depends on the environment and skill of the developers and if they understand DotNetNuke enough to sort out any issues you migh find.

And then there are others who swear they'll only install the build before - or every second build, or builds with even numbers.

If you do have problems, the forums here are fairly well moderated and enough topics to help sort out any issues you may come across.

So I didn't really answer you question, but hopefully gave you enough information to make a decision based on some more insight.

Nina Meiers