2.3 is very stable as far as crashing is concerned, and pretty good as far as errors go (which is to say that there aren't many, but I've been having a problem dealing with folders for a while now). However, it's still in fairly early development--some things change fairly unpredictably.
Installation is definitely a non-trivial exercise--you need the latest PHP, you need a very recent PEAR (though I understand that the very latest versions of this break with the latest released PHP), you need to get the latest horde and IMP via CVS, and you need to walk through all the config files and make appropriate edits manually.
I wouldn't say a definite no to a howto, but probably not at this time due to the complexity and the frequent changes--makes it difficult to support. The above should get you started, though, if you want to take a stab at it. Thanks for the kind words on the other documents!