Several days ago I sent an email to Yongnuo USA asking them:
If I buy a Yongnuo flash from you, how is the warranty handled?
1. You replace the defective unit immediately
2. You repair the unit locally
3. You send the unit to China for repair. If this is the case, what kind of shipping is used, what is the average turnaround time, and who pays the shipping?
To date have not received a reply. So tonight, I just sent them one again. We will see!
If you're THAT concerned about getting a dubious one-year warranty just pay three or four-times what you need to and get a Nikon-branded flash from the start.
Some people will want to know this info ahead of time to weigh the pros and cons of buying a Yongnuo brand flash. While their cost is far less than a comparable Nikon flash, if the buyer has to pay shipping for warranty work, it will reduce (and possibly nullify) any savings over buying Nikon. So yes, some people will be THAT concerned.
I have both an SB-700 and SB-910, and when I take photos at my church, I reach for the SB-910 because it is more powerful. Is there a Yongnuo that is comparable in power to the SB-910 that also offers HSS?