Although I've not really used Raisonance (yet), one thing which struck me when looking at their website was that they have a far wider range of price options than Keil: with Keil, if you want 'C' and a full debugger, but only need modest code size, you still have to shell-out for the full top-of-the range package which supports code banking, data banking, 24-bit address spaces, RTOS, etc, etc, plus cherries on top!

Raisonance certainly looks more economical for smaller projects!