I bought the 24-70 f4 IS from them on eBay.... pretty sketchy listing. I was messaging back and forth trying to ask if it was imported/grey market, and even specified that I am asking because I expect it to come with the Canon US warranty. They are physically located in New Jersey and their listings do not specify that their stuff is grey market. Only after bidding on the item did they come back and say "it IS imported" and asked if I'd like to cancel. I immediately replied say that I did. hours later I got an email from eBay confirming that the package was shipped. So I messaged again to tell them, and asked that they cancel the shipment since they had already offered cancelling the transaction as an option and moved forward without waiting for my reply.
They replied back suggesting that I refuse the delivery and then contact them again to do the return later. Needless to say I was pretty frustrated at this point.
I wrote back once more saying that I did not want to do that and tie up all of that money for 2+ weeks, and asked one more time if they would cancel the shipment. I said I would leave positive feedback on ebay, google, reseller ratings.com, etc... otherwise I would do the opposite.
This time I got the quickest reply (and nicest). They told me that there was an error and that the lens WAS a US model with a warranty. At the point I just said F it, and waited to receive it. The lens that they did ship, did have a warranty, but came in an unmarked box. It was $100 cheaper than B&H so whatever... Still, I suspect that they might have switched it with a legit model to avoid bad reviews. Because as a 3rd party vendor, especially on eBay, marking a warrantied product as such is definitely a selling point, right? I think they would know that.
Anyway that was my experience with them. At least you have the clear answer up front about the warranty for this 5D....