My go to place for the watch business
I sell watches on Grailzee and more often than I should, I buy them too. I like the different formats they offer for selling and with some patience it is possible to find good deals when buying. The strong point with Grailzee is their authentication service. You can definitely trust them to do a good job. Having professionals handling your purchase or personally managing your sale is well worth the money invested. Just don't be greedy and post reasonable asking prices: you'll do great.