Today was a pretty big day for Mac users. Apple finally released Mountain Lion, the next iteration of its OS X desktop operating system. It’s currently available on the Mac App Store for $19.99.

After having used Mountain Lion for a few hours now, I’ve come to really love it. Lion was great – and Mountain Lion is just an improvement upon the previous OS. It’s smooth and zippy; it adds a number of new and improved apps, including Messages, Notes, and Reminders; and the GUI was tweaked enough to keep the admittedly old OS X desktop feeling fresh. And most importantly, that updated GUI doesn’t have any adverse effects on performance. In fact, Mountain Lion feels even faster than Lion.

However, I’ve run across one app that doesn’t work so well with the new system: Firefox. Unfortunately, that’s my mobile browser of choice, so I guess I’m just going to have to wait until Mozilla updates whatever is wrong. Of course, Safari 6 was released with Mountain Lion and, like the rest of the operating system, it works very well.

Other than the minor Firefox complication, Mountain Lion has given me no problems so far. I hope it stays that way, too. Of course, your experience with Mountain Lion may differ; if it does, take part in our poll below and leave a comment telling us how hard the cougar has bit you.