Hi Leon,
I have not tried buying from this supplier and I admit it's difficult to assess when they seem to have a lot of positive feedback (but negative reviews as well). My take is: If they can source these watches as authentic and brand new then why can't the manufacturer warranty them?
Our guarantee applies even though some items may not be covered by the manufacturers warranty, because JOMASHOP.com is not an "authorized" dealer of the merchandise.
The warranty is with the manufacturer and not with the dealer. "Satisfied" buyers are claiming to have found a gray market in Jomashop with a fraction of a cost for the real high-end watches. It could have been a good discovery but several reviews argue the watches are fakes. Please read this Link hidden: Login to view and hopefully it can help you decide.
Remember: Nothing beats peace of mind from the protection granted by the manufacturers. You can see their list of authorized dealers from their websites. Or you can also confront them with this issue and once and for all try to get a straight answer from them too.