>>>But every rewrite I've ever been involved with always cost more than planned. That needs to be considered too.
>
>Agreed- not least since in January 2013, rewriting in anything that is not open source (and therefore cannot be summarily Foxed) is like jumping from the frying pan into the fire. If ever there was a time to make haste slowly, this is it.

Do I understand you correctly that you don't think anything but open source is viable?