Joel’s made a pretty good post about choices == headaches. He doesn’t mention macs anywhere but it’s the silent alternative to what Microsoft are Linux are doing wrong.
I have some addendums though:
On macs there is usually a convoluted (in the sense of non-obvious key modifiers and the like) way to do even more than microsoft even offers. Hence, if you absolutely positively need to use some little used option, it’s one google away. In practice this works extremely well. A lot of successful software products use similar tactics. You can tweak firefox to minute details in about:config, but the preferences options are (relatively) clean and obvious, as they should be.
This whole choice = headaches deal also applies, I think, to the java world. In e.g. ruby, if you want to build webapps, you use rails. Pythonistas already complain internally that the triple offerring of web.py, django, and turbogears is confusing, superfluous, and advocate combining the projects into one.
Java-side you have at least 10 offerings. I can see at least one way to fight this as a contender on this very very busy marketplace: Market yourself as web framework first, with ‘java’ being a detail, instead of the other way around. Rails take this tack (it’s Rails on Ruby, not the other way around).
Paradoxical, isn’t it? More choice is somehow a net negative in many circumstances.