http://forum.rl-team.net/showthread.php?t=1982&page=2

Here is a short list of what that free version lacks in comparison with the pro.

Quote:

Render-to-Texture Effects
Create water with realtime reflections & refractions, surveilance cameras, or use it to create your own full screen post-processing effects.

Full-Screen Post-Processing Effects
Use our built-in image post-processing effects like Glow, Motion Blur, Color Correction, and others, or create your own custom ones. See image effect docs

Realtime Shadows
Unity Pro supports realtime shadows with self-shadowing that just work. Read more
Without Unity Pro it is of course still possible to use lower-end shadowing techniques, like Lightmaps or Projectors.

Profiler
The Profiler in Unity Pro helps you to optimize your game. It reports how much time is spent on rendering, animation, physics, your game logic etc. Read more

Low-Level Rendering Access
Need to use custom rendering techniques, bypassing Unity's rendering pipeline? The Graphics and GL classes give you access to the bare metal.

External Version Control Support
Unity Pro now supports an alternative way of saving metadata for better external version control. When enabled, version control systems such as Subversion, Perforce, or Bazaar can be used without losing import settings or references between assets.

C/C++/Objective-C Plugins Support
Have a custom native library that you absolutely must use? Use a C, C++ or Objective-C plugin to directly call into it. See plugin docs

Video Playback and Streaming
Import and play back videos. Stream them from the net. Put them onto any 3D surface, or display them in 2D on top of your game. Read more

Fully Fledged Streaming with Asset Bundles
Stream in anything to the web player or application using Unity's Streaming Asset Bundle features. Textures, animated models, complete or partial scenes, new missions and expansions, user-generated characters.

Script Access to Asset Pipeline
Get direct access to Unity's asset pipeline from scripts. Need a build machine that churns out builds 24/7? It's just a few lines of code.

No Unity Splash Screen or Watermark
Standalone games and iPhone games will not display the "Made with Unity" splash screen. Web player games will not display the 5 second Unity watermark.


As it stands the free version is much worse than the cracked 2.5 Pro


1st prize: Lite-C and Newton 2.17 by Vasilenko Vitaliy

Newton2 videos: http://tinyurl.com/NewtonVideos
LiteC+Newton2 discussion: http://tinyurl.com/NewtonWrapperDiscussion
Latest LiteC+Newton2 version(v23, from 29.10.2009): http://depositfiles.com/files/ae1l0tpro