Glad to see this!  I was surprised to find a 3D SW at version 5 on Mac I had never heard of!  Well, bigtime Maya/Bryce user likes it more than a bit!  Very quick learning curve, I have pretty much tried everything but the animation and rendering end.  I was pretty much productive right away, tutorials are efficient.

There's a lot I don't understand yet, but I can offer some things.  (I bought 12/22/2009)

1. It allows arbitrary connections of lines and points into polygons, etc.  Not many low-end packages can claim this.

2. It has a nice set of polygon manipulation tools, but it's weak on some things.  It's tricky to control the subdivision for example, and numerical entry is a mystery to me yet.  Yet the Java Script interface seems to offer a way around almost anything.  (Very cool feature)

3. The Point/Edge/Polygon paradigm is not bad, but trying to dig into whether we in fact have two edges and four points or one edge and two points at a junction of two polygons is hard to fathom.  Needs a mode like Bryce, where a pop-up can be used to see everything that you spear with your selection ray.

4. Texture UV tools A++

5. Great for healing anomalies and degenerate models, (and Maya makes a lot of them).  For example I have a 20MB spacecraft of several thousands of polygons.  Maya unfortunately is glib about generating extra verrtices, compressing UV down to very small parts of textures by default, and leaving loose points, un-normaled faces, on and on.  That's the power of a RAW tool.  Bring it in to Cheetah 3D, and you can see everything very clearly.  C3D has an optimize tool that cleans up models A++. 

I could go on.  But given all of the pain of Ray Dreams, Strats 3D, Extreme 3D, etc, etc, from the 80's and 90's Cheetah is clearly part of the next generation.  And the price is sweet!