My experience with a Samsung Series 9 and a Samsung Series 5 is quite similar. I have switched my home router from a TP-Link WR941N to a WDR3600. I have had no problem since in the Series 9.
The Series 5 connects to an access point WA901N and has all the well known problems.
In my office I still use a WR941N and I have had some problems, never in the magnitude of what we read in this posts. I believe that the way the router manufacturer has implemented the N protocol in the routers has something to do with this problems.
Intel, wake up !!!!!