It was a hard decision between two good projects and there was also a big bunch of work connected to the change. But to learn something new is one of the major aims (beside having fun and creating a game). Now the first basic application is running, many pages of documentation have been read, and I have got some new skills in Blender.
The reason I took the workload on me to change the engine was to get a specialized graphic engine with support for all mayor platforms (Mac, Linux, Windows). For getting a specialized graphic engine with many features, tools and a big community I “pay” the price to use third party tool kits for example input handling or window system.
If you are searching for a toolkit to visualize something in 3D, control the output via mouse or keyboard and navigate thru the virtual world without reading many sides of documentation and many writing many lines of code than the right choice is Irrlicht for you. Its easy to master the basics, clean API, runs on many platforms, compact all in one solution and has a very good render performance.
If you want a graphic engine which does perfect graphic rendering with high performance but nothing else than Orge3D is the right choice you.