Hi Smileycake,
You may have seen this but just in case … post #2 here has links to all the Australian threads on the forum and includes a link to a post with a long list of Australian manufacturers (including ozmattress).
Buckling column gel is a high quality material that is very durable and quite different from other types of comfort materials. Of course it is also not the only material in the comfort layers so knowing the quality of the other materials is also important (as you clearly know already). 3.7 lb memory foam is on the low side and just under the somewhat arbitrary number I usually use as a minimum guideline for memory foam which is 4 lbs but thinner layers will also have less effect on the durability of the mattress than thicker layers of lower quality materials. Once you are in the range of about 2" or so of lower quality materials in the upper layers of a mattress I would begin to become quite cautious regardless of the quality of the other layers (I would use 4 lb memory foam and 1.8 lb polyfoam as the guideline for foam density below which I would begin to be cautious about lower densities in thicker layers than about an inch or so). The pocket coils appear to be good quality and the support core of a mattress isn’t the weak link of a mattress anyway. The closer to the4 top of a mattress a material is the more its qualities will affect the overall durability and longevity of the mattress.
When you are considering an online purchase … one of the most important parts of what I call your “personal value equation” would be the risk you are willing to take of making the wrong comfort choice when you can’t test a mattress ahead of time and the return or exchange policies of the manufacturer or retailer that determines the options that you have after a purchase that can help reduce the risk. This is an important part of the “value” of an online purchase if you aren’t confident that you are making the most suitable choice possible or familiar with the materials in a mattress you are considering.
Like all good quality materials … the choice between buckling column gel and latex is a preference and would depend on which mattress was most likely to provide you with the best PPP (Posture and alignment, Pressure relief, and Personal preferences) because the design of a mattress will have more to do with how suitable it is for your specific needs and preferences than the actual materials. It would be important to either test a similar mattress locally to get a sense of how an unfamiliar material feels and performs or alternatively make a choice based on more detailed conversations with the manufacturer where their descriptions and knowledge of their mattress and how they may fit different body types and sleeping styles can be a guideline based on the “averages” of other people.
The mattresses at ozmattress appear to me to have reasonably good value.
Phoenix