It is irregular. Today, only dropped once. Yesterday, dropped 4 times including twice during raid (had to be in a channel). Today wasn't in a channel. Not as likely to notice a problem if I'm just solo as I'm not using the chat, unless I happen to try to access the Internet and find myself unable to do so.
One very peculiar trait of this vivox-related dropping of the Internet browser (using IE8) is that it will sometimes give the normal "can't find this address" error message and sometimes it will give an "invalid address type" message. When it does that, I find in the address bar instead of for instance http://forums.station.sony.com, it reads http:///.
The Cisco unit is provided by Time Warner Cable (Roadrunner), but the Netgear box is my own. To reiterate: I ONLY get this peculiar outage from the Vivox voice chat interface. Never if I'm not in game. Seldom in game unless I either have voice chat on and using a channel (often), have voice chat enabled but not using a channel (sometimes) or have voice chat off but changed characters and it informed me I have new voice chat channels available (seen it twice that I know of). The other thing is this: When I was unable to even bring up voice chat from options, as SOON as I opened Station Launcher with another account (hadn't even logged onto a character or character select yet), suddenly the voice chat interface appeared on my original account's character screen. Of course, normally logging in a second account drops me from voice chat on the original account and I must reset it and rejoin, always been like that for me. But the voice issue happens even with only one account running on this computer.