Hi LisaMocha,
Talalay generally has a milder smell than Dunlop that some people describe as a “sweetish” smell like vanilla or sugar cookies rather than the more rubbery smell of Dunlop and it tends to dissipate more quickly (see post #2 here).
I don’t know other than knowing that they are all good quality covers that are quilted with wool. I would suspect that both the Sleeptek and the GreenSleep would have more wool in them but you would need to find out the more detailed specs of each cover directly from each manufacturer to make more detailed comparisons or have them provide more detailed descriptions (the specifics of the cotton and the amount of wool etc) but this still wouldn’t tell you how each will actually feel to you until you actually lie on them.
All of these mattresses use good quality and durable materials (you can read more about the different types of latex which may help you make better comparisons in post #6 here). You can also read a little more about the difference in “feel” between Dunlop and Talalay in post #7 here but the only really reliable way to know which you prefer is to try both types. None of these mattresses have any weak links in their design.
The Flobeds would have the edge in terms of being more customizable (more like a custom made suit rather than a suit off the shelf that you can make some adjustments to).
No matter which you choose you will end up with a very high quality and durable mattress but final choices can be very difficult when there are no clear “winners” and will depend on all the objective, subjective, and intangible factors that are most important to you.
Phoenix