Of course, no installation or software upgrade is without problems.
WordPress 2.3 downloaded quickly and I was able to install onto my server in less than 10 minutes – but, it seems that some of my favorite plugins, namely Google Sitemaps Generator and Ajax Comments are incompatible with 2.3 currently. Popularity Contest is also generating some SQL errors, so I have deactivated it, also.
If you have upgraded to 2.3 and see weird stuff going on, check out the Plugins/Plugin Compatibility page.
If you want some ideas on some cool WordPress plugins to install, check out my Site Design page.