My older Roku player (this model, N1000-B) died a couple of months ago. The wireless NIC went out to lunch for some reason, showing 00:00:00:00:00:00 as its MAC address and totally unable to see any wireless networks, just as described here. I was busy and lazy at the time, so we just switched over to watching Netflix streaming content on our Wii instead.
Last Friday I finally got around to calling Roku about the issue and the technician that I got was very helpful. He didn't give me the "reboot runaround"; he just asked me what troubleshooting steps I had taken, and ensured that my MAC address was showing all zeroes. After a bit more discussion, he offered to replace the unit for free, even though it was nearly a past its warranty expiration. They mailed the replacement unit (looks like it might be factory refurb?) via FedEx and 3 business days later the new unit was in my hands. The new unit setup was painless (as expected), and a return shipping label was included so even the round-trip shipping was free.
I was extremely pleased that Roku stood behind their product, even after it was out of warranty. They did exactly the right thing to change my mind from "I'll never buy another one of these" to "I'd happily buy something from them again."
(full disclosure: I have no affiliation with Roku, other than being a fairly satisfied customer)