With Unity free getting real time shadows what are the major differences with Unity pro and Unity Free now?
Lots of things. Global Illumination, image effects, profiler, occlusion culling, soft shadows, deffered rendering, dynamic batching etc. There are loads of features still worth buying pro for.
As before said, a lot is different. However, realtime shadows for directional lights == awesome. Seriously, UnityFree needed this a long time ago. Shadows isn’t something you can just hold hostage!
Audio filters
Hard shadows with directional light >> Unity Free V4.2.x 
Render to texture == best feature evah!
Gigi
Don’t forget the profiler.
I didn’t ;).
Also there is no Unity logo at the start in Pro which is an important “non-feature”
Sexy black skin.
Oh, I was speaking more to Gigi
If you dont want to make more then $100k a year you dont need to buy pro
the price!
And, perhaps most important for quality games, unity free has disabled gpu operations…
“real time shadows”…
I only knew about the mobile licenses, but this is, just awesome!
Also, the Profiler, RenderToTexture, Black Skin, etc.
My favourite Pro feature: scripting the build system. Start multiple builds from a different location, go for coffee, then download the (partly) pre-tested binaries from a website 15 minutes later.
Don’t forget the extra mechanim features