Hi Vampirtc,
I’m assuming that you’ve read the mattress shopping tutorial here but two of the most important links in the tutorial that I would especially make sure you read are post #2 here which has more about the different ways to choose a suitable mattress (either locally or online) that is the best “match” for you in terms of “comfort” and PPP (Posture and alignment, Pressure relief, and Personal preferences) that can help you assess and minimize the risks of making a choice that doesn’t turn out as well as you hoped for and post #13 here which has more about the most important parts of the “value” of a mattress purchase which can help you make more meaningful quality/value comparisons between mattresses in terms of suitability (how well you will sleep), durability (how long you will sleep well), and the overall value of a mattress compared to your other finalists (based on all the parts of your personal value equation that are most important to you).
I don’t have any particular knowledge about the German market so I won’t be able to help in terms of specific retailers or manufacturers I’m aware of there but the brand name of a mattress isn’t particularly important anyway because outside of how suitable a mattress is for you in terms of PPP, a mattress is only as good as it’s construction and the type and quality of the materials inside it (see this article and the quality/durability guidelines it links to) regardless of the name of the manufacturer and the mattress materials that are used in Germany would generally be the same as the materials in North America (see post #5 here about “brand shopping”).
The only caveat is that in North America the foam density guidelines for polyfoam and memory foam that I would normally suggest are expressed in lbs/sq ft while in Europe they are often expressed in kg/sq meter so you can use the online density converter here to “translate” them.
I would tend to look for smaller local and regional manufacturers/retailers or online manufacturers/retailers that are completely transparent about the type and quality of all the materials that they use in their mattresses so you can make more meaningful comparisons between mattresses and identify any lower quality materials that could be a weak link in any mattress you are considering.
While I can’t speak to whether any mattress is a good “match” for someone else in terms of “comfort” and PPP or what you will “feel” on a mattress … I can certainly speak to the quality and durability of the materials inside it. If you can provide the information listed here about the type and quality of the materials inside the mattress you linked (or the equivalent European specs which I can probably translate for you) I’d certainly be happy to make some comments about the quality and durability of the materials and the mattress as a whole.
Gel memory foams (and other types of gel foams) include a very wide range of different materials with different formulations so they aren’t just a single material with the same temperature regulating properties but there is more information about gel foams in general in post #2 here and the posts it links to. In very general terms … gel and/or other thermal conductive or phase change materials can have “some effect” on on the sleeping temperature of a particular material but how much of an effect they will have and how long the effect will last will depend on the specific formulation of the material and on the “combined effect” of all the other materials and components of the sleeping system including your sheets, mattress protector, and bedding. Gel materials tend to have a more temporary effect when you first go to sleep at night or over the first part of the night than they will over the entire course of the night.
Phoenix