Mine arrived today. I've only had a brief chance to test them but so far so good. Straight from the box, insert batteries, attach to camera / flashes, switch on and boom - perfect first time.
They seem pretty well screwed together. I tried a 565EX on top of the 622 in the hotshoe and waved the camera around in portrait orientation. The whole combo felt perfectly tight.
By the way, if your new 622s look scratched up, don't worry: the shiny top surface has a clear protective cover on it. It took me a minute or two to realise this because it's stuck on very firmly and has no tabs, so it takes a persistent fingernail to get it off.