Hi there,
I noticed that my best sellers are quite different from one site to another :
- Dreamstime : my best sellers are macro and close ups, business and office related (money, stationery, IT..) + people.
- Fotolia : same + architecture (office buildings...) and outdoors (parks...). Outdoors don't sell for me as much at DT.
- 123RF : very different than DT and FT... I sold a LOT of my beach/seaside images that don't sell at all at Fotolia and Dreamstime.
As I'm new at StockXpert and IS, I can't give any conclusions regarding those sites.
Did you notice any differences between your best seller categories for each site you're submitting to ?