I tested the public betas of OS X 10.10 (Yosemite) and they seemed okay, so I installed the real thing at the end of last week. So far I haven’t had any problems with applications. As usual, my local web server set-up got stomped flat, but I’m used to that by now. That’s why I make backups.
My website and email have moved to a new hosting provider, and it’s a relief. Previously, the server took up to 30 seconds to respond to page requests and my email was frequently unavailable. It’s particularly embarrassing to have an unreliable website when your main business is creating them. The last hosting company were great when I started with them but the service deteriorated over time.