Thank you for the warm welcome and thank you so much for these replies. This makes me less frustrated with all the stuff I have been reading on D600 issues. I did think about "upgrading" to D800, but that is just too much of a camera for hobbyist like me. Also, I read an article that talked about how D4, D800 and D600 has same internals -- i.e. the issues of shutter particles and such may also affect D800.
I am more comfortable now than before in staying with Nikon and not jumping ship to Canon!