Up until recently, it had a really annoying bug where it would sometimes bomb out when you did stuff in the footprint editor. There was another bug where you'd get screwy behavior if you hit F4 (to route a ratline) when none was selected. It would grab a random one and draw a trace to your mouse cursor...
There was also a bug where a new pin added to a footprint wouldn't have its solder mask cutout. It's trivial to work around if you know about it (go into the "edit pin" dialog and re-select "default" in the box for solder mask cutouts), but we did end up getting one batch of boards where somebody had to sand the solder mask off a row of pins, before I noticed it.
All of these appear to be fixed now, though.
The only annoying thing it does to me is that if you have more than two selectable objects in one place, it's difficult to select the third one. For example, if you have some reference text inside the boundary for a part, and then a trace running through there, you have to get creative to get that trace selected. This hasn't caused me any real problems, but it does give me a few seconds of frustration every once in a while.
If you last looked at it a couple months ago, there are some new features that I really like:
-select any pin or segment and hit "n" to highlight the whole net (great for double checking your work)
-after running DRC, you can hold down "d" to make all the little brown circles huge
-the manual routing is smarter in a few ways
-more capability with copper areas
-more things that can be checked automatically
-a warning pops up when you use headers with those 28 mil holes (most headers won't fit those)
-fpcroute / freeroute are integrated now (I've only used it for two boards so far, but it's a huge time saver and the results so far have been decent)
Personally, I'd say the best thing is to just check your Gerber files afterward and make sure they're right. I've never seen a bug do anything really horrible (like leave off a trace or something), but the software is being developed pretty fast so you never know what you'll run into. Checking is always good though, because it's very easy to make a mistake when so many things have to go right at the same time...