Hi npirog,
While there are always some people who don’t seem to notice a great deal of difference between two mattresses that are very different … I think it’s fair to say that most people would notice a big difference yes (depending to some degree on the specific mattresses you were comparing because the Alexis with two latex layers would be closer to an all latex mattress than one of their hybrids that only used one layer of latex).
Post #2 here has more about the comparison between a latex/polyfoam hybrid and an all latex mattress.
Phoenix