Anyone Have Experience With German Art Publishing Company May Ag?

Had a message today from them expressing an interest in producing a couple of my photos (which they found on a stock library) as prints. Given they have said that they pay royalties rather than mention prices (nor can I see any prices on their website http://www.may-ag.de/index_en.ahtml , links to their catalogues seem to be broken) I'm in 2 minds whether to accept. Does anyone on here work (or worked in the past) with them or know if they have a good reputation or not? As far as I can tell they mainly seem to sell though distributors.

Many thanks for any feedback!