I've been running powertop 2 for weeks now, and would like to see it stable. It works perfectly, and truth be told my laptop is actually unstable *without* it, due to some silly usb suspending stuff that powertop helped me discover, monitor and adjust. ;-)
1.x is stable. I'll consider slotting and stabling 2.2 but not 2.0 or 2.1 Denied.