I've been using EazyDraw for more than two years now.
EazyDraw does the job OK. It's pretty good at technical drawings, very useful for teachers who need some physics/geometric drawings for their class or people who want to draw some plans. From the bunch of mac vector apps out there it's the best choice for technical drawings, (so to say) "baby-"CAD; I mean CAD with an "easy" MacDraw-like interface. EazyDraw is quite easy to use – things like the spiral tool and the many shapes in the object libraries are great. However, for the artsy stuff, designing, etc. I felt EazyDraw not so well suited, because the cluttered interface holds back your creativity, in a way.
Well to be honest, the interface is a mess. It is fine if you are a complete beginner or you have learned drawing apps in the '80 and '90, however, since the app is quite feature rich, when used for advanced things you end up with so many pallets and menus… well, clutter, that costs you time. The UI just doesn't feel up to date and could be much more efficient.
Also, there are "rough edges" from the technical side – there are always a few bugs around, but these are usually addressed quickly in the frequent updates and upgrades.
However this brings me to another point: it is very easy to lose oversight about the various versions of this app. At the moment there are three versions of EazyDraw at the MacAppStore: ED3 (called only "EazyDraw", but with "3" in the icon), ED4 and ED5, for 15$, 30$ resp. 95$. I don't really know what's the difference between those, because description and screenshots in the MacAppStore are the same at least for version 3 and 4. Buying directly from the developer you can get another version of version 5 (as far as I have understood it), and also there is EazyDrawRetro, which opens the legacy formats (MacDraw, AppleWorks), however for this you need a "version 4 free market license". It is nice that the developer maintains a version 5 for older OSs, like 10.4. Still, the whole MAS thing has made things quite confusing with EazyDraw. One year ago there was even more confusion, with different versions having the same number (see comments below). Definitely one developer who didn't "get" the MAS right. I purchased version 3 in summer 2010 directly from the developer for 95$, one year later I had to update to version 4.1 because version 3.6.1 doesn't work with Lion (yeah right, and now a version 3 is sold at the MAS which works). Version 4.1 works now on my machine in "grace period", I have 78 days left. Probably that means the app won't work after that period. Personally, I haven't experienced a difference in features from version 3 to version 4, except for the Lion full screen mode. Many crashes and corrupted files with version 4.1 on Mountain Lion… Probably I will never upgrade to version 5 but instead will just buy the cheapest 15$ version from the MAS.
However, I haven't found a more capable app for technical drawings with this price tag (15$). If you need an easy to use "CAD"-like app, then EazyDraw is the way to go. For more "artsy" illustration jobs, creating icons, etc., I'd recommend Intaglio and iDraw (which has a great, great, great iPad version). Sketch is also a very nice looking alternative, and Artboard seems to be worth a look too.