Hi RickNY,
You may have seen this already and it would be a moot point for you since you’ve already purchased a mattress but for the sake of others that may read this … the better options and possibilities I’m aware of in and around the Long Island area (subject to the guidelines here) are listed in post #4 here.
It will be interesting to hear your feedback because the Sonata is designed to “approximate” the Sealy Optimum Destiny rather than the Genius but both the Destiny and the iComfort Genius are in a similar firmness range so based on extrapolating the firmness of one for the firmness of the other you probably made a suitable firmness choice although the “feel” (which is much more subjective0 may be different between them.
All foam manufacturers make high quality and low quality foam so it would depend on the specific foam you are considering. Like all the other foam manufacturers … Carpenter provides foam for many mattress manufacturers that is used in both low quality and high quality mattresses.
The most important single factor in the durability of polyfoam and memory foam is its density (regardless of who manufactures it) but there are also many other variables that can affect the durability and useful life of a mattress besides just foam density that are discussed in post #4 here and the other posts it links to. As you can also see in post #2 here … the useful life of a mattress is also relative to the person. A mattress that is “on the edge” of being too soft for someone may only last a relatively short time before they cross the thresholds from sleeping well on it to sleeping OK to “tolerating” the mattress to finally deciding to replace it so there is no way to quantify how long a mattress will be suitable and “sleep well” for any particular person.
In more general terms … you can make meaningful durability comparisons between two mattresses based on “this one is likely to last longer than that one” based on the quality of the materials but it’s not possible to quantify how long either of them would last for any particular person. Having said that … none of the Novosbed mattresses have any obvious weak links in their design and assuming that it is well inside the range of a mattress that is suitable for you in terms of PPP … it would be reasonable to expect that for most people that aren’t in higher weight ranges that it would “sleep well” for somewhere between 5 and 10 years. There is also more about the general foam quality guidelines I would generally suggest using in post #4 here.
Most importantly of all … congratulations on your new mattress 
I think you made a good quality/value choice and I’m looking forward to your feedback after you’ve had the chance to sleep on it for a bit.
Phoenix