In my experience Select 4.37 and RO5.06 seem equally stable, and work fine. I don't really see the point in fiddling with either of them anymore.
There are many other things such as video viewing and editing software, Real Audio/streaming audio, JVM that we are still no nearer to having under RISC OS that other OS users take for granted and expect to find bundled with their new computer.
So what is the point of trying to 'improve' the OS when IMHO the effort should be going into 'improving' the range of things we can do with a RISC OS machine?
At least new hardware such as the Iyonix offers the opportunity to do more things under RISC OS (such as PCITV and Cino).