Well no, under the hood advancements rarely slap a user in the face to the point where they realize the benefits. Given the advancements in memory management, cpu task handling, etc this is the mythical "power user" update that so many have begged for...but of course the average consumer won't notice. That said, they'll probably be pretty happy with improved battery life.
But my iMac doesn't use batteries TBH in the time I've owned this iMac the CPU has yet to break sweat, same with the RAM. Point is it's not simply a case of a small outlay for the new OS, many third party apps may need to be upgraded, Parallels to name but one.