Also been with Vonage for quite sometime and, until today, never a problem. Today's issue (a sucky one): I'm in Europe and the router basically locked up during firmware upgrade, so no service now and no reset possible. Solution: Sending out a new one. No charge for shipping or for the replacement, as long as I return the dead beast within two weeks. Said they'd refund my shipping, too. They're sending a replacement out tomorrow to arrive Tues a.m. at my stateside address. If I weren't sitting in Europe right now, I'd say they handled it well. I can at least still get voicemail via e-mail/web and will have to use SoftPhone for outgoing calls.
Stinks a bit that they can't handle shipping overseas, or at least U.S. military or embassy addresses. Also, they don't come with 220v-capable power supplies, but instead, Linksys sells them aftermarket at a nice markup. The replacement should be compatible with my Power over Ethernet - 12V.
I do think I'll pick up a spare router for situations like this--may never happen again, but if it does, I'll be ready.