Hi ernie,
You can see some of my thoughts about the vZone in post #6 here and post #2 here may also be helpful in comparing both options.
Convoluted layers involve a tradeoff. They have a wider range from softness to firmness as they compress and start off softer and then get firmer faster than a solid layer but it does so at the expense of durability (there is less material to distribute and absorb ongoing compression forces). The disadvantage of this design which only has a single option for the top 2" is that there is less flexibility in layering and all the “designing” happens below the top two inches. With a design where there are more choices for a top layer … there is more design flexibility in the mattress.
The vZone can also add complexity and as the post I linked mentions it can either be detrimental or helpful.
Having a tension adjustable Euro Slat foundation can also be overkill IMO with a thicker mattress and would be more suitable with a mattress that was only 6" or so where it can be a more important part of the overall design of the “sleeping system”. While it can have some benefits with a thicker mattress as well … these benefits are reduced (or in some cases it could be counterproductive) with thicker mattresses where the latex layering would provide the combination of pressure relief and support that is needed on top of a firm non flexing foundation and would reduce the effect of the flexible foundation. It would be an expense that I normally wouldn’t consider justified with a thicker suitable designed mattress and I would prefer the combination of latex ILD’s and the layering design of the mattress to do the job of providing pressure relief and alignment.
I haven’t seen either cover in person so I can’t make a direct comparison from personal experience but they are both high quality and I would say they are roughly equivalent in terms of quality (at least if you chose the equivalent wool quilted cover from SleepEz).
There is a link to a foundation in post #15 here which combines many of the benefits of a tension adjustable base and a firm non flexing base at a much lower cost.
Hope this helps in your decision.
Phoenix