I've seen comments by prominent RISC OS users which have asserted that most serious RISC OS users have upgraded to the Iyonix. If this is the case, I think the figure of 600 is a cause for concern.
Fortunately, I don't believe it to be true. The attitude I describe - that 'serious' users are Iyonix users - has caused an unhealthy polarisation of the market. For example, some Iyonix users, including Castle representatives, dismiss RISC OS Select driven, it seems to me, by an arrogance or a need to feel that they've chosen the winning camp. Similarly, some Select supporters have pretended that the Iyonix doesn't exist.
Clearly there is merit in both of the two major RISC OS groups. RiscPC owners, like myself, are still regularly buying stuff to sustain the tiny amount of commercial software development that occurs - as, I'm sure, Iyonix users are.