Hi Homer12.
Welcome to our Mattress Forum! 
Yankee Mattress used to be a member of the TMU a few years back. Something like this is oftentimes a business decision which in their case was connected with the manufacturing of custom mattresses for specific needs and with major website changes.
Subject to confirming that the components within the mattress you are considering from Yankee (or anywhere else) meet the quality/value guidelines here for your BMI, (see this article ). They can certainly be a good source for purchasing a mattress. Being a local business with a showroom has the great advantage of consumers’ ability to test any mattress they consider and making in-person comparisons. Typically, in-store testing has the best rate of success in terms of finding the best fit.
Best of luck with your purchase.
Phoenix