Thanks for the information! I get a sense from some of the replies that there are many people out there who don't like the S mattress brands. I have been using the S brand mattresses for over 20 years with no issues until this most recent issue with the edges of the pillowtop shifting. The response from Glenbury was the first I have heard of someone trying to steer me away from a pillowtop mattress. Prior to purchasing the Sealy Midnight Serenade King mattress in 2010 we had a Sealy pillowtop Queen mattress that is still in use today in my daughter's room. It's still quite comfortable after over 15 years.
So far none of the responses addresses my main question on whether or not the traditional innerspring coil or pocketed coils would be better for comfort and long term durability.
I definitely agree with SleepEnthusiast that they new mattress will be more firm until the materials are broken in, but our 2010 Sealy Midnight Serenade was definitely softer from day 1. The sales specialist indicated that an additional layer of latex was added along with the stiffer springs that resulted in a slightly firmer feel. Part of me thinks maybe this is a good thing and that the added layer of latex and the stiffer springs will result in a more durable mattress.
To SRNH's comment, I doubt Sears is going to allow me to get my money back after 2 years, and even if they would I would end up on the short end of the stick because I got the mattress on a deep discount when they were clearing out the previous year's models for the new models.
I still haven't called the Sears mattress warranty department back to let them know that the only mattress I could find with a similar comfort level and feel to our old mattress was a Simmons Beautyrest and not a Sealy. They are at the same price point, but I don't know if they will let me switch mattress suppliers.
Thanks for the information! Any advise you could provide on innerspring vs. pocketed coils would be great!