Its probably a misunderstanding, but QNX has a very strong memory protection model that extends to its driver stack. Given that its a true realtime/microkernel, which has its own set of problems, but memory protection isn't one of them. For a number of cases QNX is going to be a large step up from linux.
http://www.qnx.com/developers/docs/6.5.0/topic/com.qnx.doc.i...