Hi jaybackintheday,
The main differences between them are the Bamboo bliss has a higher density and more durable base foam, a more generous exchange policy, and a more costly cover which includes wool in the quilting (which can help with temperature regulation). The Talalay latex is the same in both mattresses.
Unfortunately there is no way to put a number of years on the useful life of a mattress for a particular person because there is no way to know with any certainty when someone crosses the “fuzzy line” and begins to “tolerate” a mattress just a little more and enjoy it a little less than they did some months or a year before and when they finally conclude that the mattress isn’t suitable any more and decide to replace it. It will also depend on where you are inside the range of comfort and support that is suitable for you because the useful life of a mattress is also relative to the suitability of your initial choice in terms of PPP and how much “room” you have for the materials to soften (see post #2 here). This is one of those processes (like aging in general) that creeps up on people and most people will need to replace a mattress because of the gradual loss of comfort and/or support not because the materials have completely worn out.
What I can say though is that the Eurotop would be a less durable choice than the Bamboo Bliss at your weight because you will be compressing and stressing the layers below the latex more than others that are in a lighter weight range. I would generally suggest that you purchase the best quality mattress that you can comfortably afford because it’s not just how long you sleep on it that is important but how long you sleep well on it as well.
Phoenix