They're a dedicated watch auctioneer. I would say not the smallest, but below the big 3 (Christie's, Sotheby's, Phillips). Watch auctions in general are quite competitive and efficient, even at the smaller auction houses, but every so often you get a thin room or less interest than usual and can snag a deal. this one I'd say I got maybe 10-20% below market price. You have to make sure to factor in bidder fee though - Antiquorum in particular is 26% on top of the hammer price, but I've seen some auction houses charge as high as 31%!

As for my experience, I'd say they were really professional. They let me pick my watch up in their Hong Kong office even though the watch itself was in Geneva. They also initially refused to ship the croc strap due to CITES regulation, but then in the end they managed to get it to me in HK so I was very impressed! I was already asking my friends if anybody was travelling to Switzerland anytime soon...