I spoke with an AppleCare rep about this problem and wanted to post the substance of our conversation for everyone's general info. In a nutshell, don't hold your breath for an Apple "fix".
The rep stated that Apple does not consider this a "known issue" because iCloud push works for the vast majority of users. She described the problem as "relatively rare" (she gets iCloud push-problem-calls "only once or twice a month") and described them as solvable on a case-by-case basis with a focus on each individual user's iOS 5 device and settings.
In other words, Apple believes the iCloud push problems are varied and lie within our devices and settings. So there is nothing to fix but me, you and our stuff.
The rep then suggested that I check settings on all computers and devices, then reset my iPhone 4.
When I indicated that I had done this and achieved only a temporary fix, she graciously offered to sell me an extended AppleCare policy for my iPhone 4 (mine expired 60 days ago) so we could delve more deeply into "my problem."
She also suggested that Apple doesn't necessarily monitor these boards for issues because tens of thousands of AppleCare calls each week more or less do that for them.
These are all loosely her words, not mine. And while she was entirely distant and unhelpful she was not rude or deliberately insulting. And of course, she is not an Apple spokesperson and her words may not reflect Apple's views. But the call sucked, and rather than wait for a "fix" I think we should keep at it.