one of infinite monkeys said:
as a matter of fact: Cocoon is extremyl powerful, stable and flexible. there are companies, that use Cocoon *because of performacne considerations*; as Cocoon proved to be faster then other server tools.
Erm - what other server tools?
The context of the question was XSLT processing, and I have indeed encountered one monumentally slow XSLT module[1]. I guess if you compare to that, then cocoon or anything else comes out as much faster. But if you take any implementation worth looking at from this (or last) year you can expect a different result.
moreover, you have various options to speed up Cocoon applications using fine grained caching strategies, as an example.
Likewise Apache 2 with a sensible XSLT filter.
Oh, and of course XSLT is just one application. If you want to suggest another, that's fine: I expect I could implement a faster version of XYZ with Apache 2, FWIW. That of course excepts jobs where "java" is part of the requirements spec; maybe where a company is heavily locked-in or the pointy-hairs can't grasp the difference between a tool and an outcome.
additionally it has a vivid community with good support in the mailing list for users as well as for developers. it is probably one of the best Apache projects.
httpd doesn't do too badly ...
So I really would like you to really evaluate a project before you write dubious stuff like to one cited above.
Fair comment on the OP, but IMHO your post may be in danger of making a similar mistake, praising a product by comparing it to unspecified and perhaps inappropriate competition.
Hmmm ... I'd better shut up now; I'm probably falling straight into the same rhetorical trap.
[1] it was based on Sablotron, and running the commandline "sabcmd" from CGI was several hundred times faster.