Hi yserius,
I have little knowledge of or familiarity with the specifics of the European market but in general the same “rules” and guidelines of choosing a mattress based on materials and brands would apply. Post #1 here is the first place I would start because it has the basic information, steps, and guidelines that can help you make the most informed decisions and make more meaningful quality and value comparisons between mattresses based on their construction and the materials inside them. The contents of a mattress are always more important than the brand label.
I would also keep in mind that your recourse and options after a purchase can be an important part of your “personal value equation” and if you buy a mattress that has to be shipped overseas then in practical terms any exchange or return options for either layers or the mattress itself may not be practical because of the cost of shipping so you would need to make sure that you have a very high level of confidence that any mattress you purchased would be suitable for your needs and preferences in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences).
Phoenix