helicrew: I am pleased to report that since the latest update mine is back to it's old (pre ICS) self with regards to stable wifi and no deep sleep issues and no reboots. Also no further need for wakelock?
I too got the .21 update OTA this morning. I have put SetCPU back to the standard settings and left Wakelock disabled and will await the outcome. Reports from overseas haven't been very positive so I won't be holding my breath. The .17 firmware would sometimes go a week without rebooting and at other times would reboot a couple of times in one day. So it is wait and see, and hope ASUS are still working on it.