Since I upgraded to the latest version of the 2700hgv (New machine) I have found it very stable indeed.
I rebooted it a week ago to see how fast it could run, it sync at 7495 and this morning did a speed check and it downloaded at 6379mb which is the fastest I have run at for quite some time ;D
Good news, Den. :)
I've also got v6 firmware now on a brand new unit and found it a doddle to set up (no tricks needed or anything) and its been as stable as any other version :)
my 99p router is using v6 too, after the initial shock, I now prefer the interface.
I too now use the V 6, it's just a pain having to turn Openzone on and off when changing device permissions