Thanks for your input, Richard - I bought my ZCO from you; it was a great sales experience, and I've sent prospective ZCO buyers your way.
I'm not at all surprised to hear of a likelihood that ZCO would have fixed any post-warranty illumination problem at no charge. It was just that the totality of circumstances didn't quite get me to the tipping point of sending the scope in... I do have to say that the uncertainty regarding potential repair cost was a factor. Had my scope actually sustained some damage when my rifle fell, then it would have been a no-brainer to ship it for repair on my dime. The illumination essentially works; it's just not bright enough for daylight use and I think it's supposed to be. It's just not important enough to me to go through the process.
Your reasoning around who pays for shipping and under what circumstances is perfectly sensible. If ZCO had provided the label, that would have been incentive enough to ship it for inspection, but the trivial cost to me in this particular case was just enough to stay my hand.
Getting back on topic for the thread here: hopefully this foray into warranty differences between Vortex and ZCO is useful in OP's decision process. I would think a heads-up comparison of optical performance between the two would be the major deciding factor, and my $.02 on that is in post #6 above.
-Richard