Linux is comparable to Windows 7 (NT) in terms of RT, that is completely off the charts regarding RT but good at running tons of processes where exact timing is no issue, like on a PC. For mobile phones, running tons of processes has limited advantage, but RT capabilities becomes increasingly important when the HW spec gets lower and simpler. Nokia is in the need for something that also work well in the sub 200$ range to replace Symbian, and that doesn't suck the life out of the batteries in a couple of hours.