I guess how "big" an upgrade this seems depends on how tech savvy the person is. I've noticed that to the layman, if there's no visual eye candy, they think nothing happened. To a person who's familiar with how software is written & works, Snow Leopard would seem like a fairly important upgrade w/ all the under the hood stuff.
I work at an elementary school as their techie. Last summer I worked with the techs who work district wide. We basically took out each of the 9 school's wireless systems and replaced them, as well as organized the switches/network cabling to be easier to manage. We did this to basically increase wireless performance and make it easier for us to manage. But this was a huge project that delayed many other things (like updating the software on the computers). A lot of the teachers at my school didn't understand that there's stuff under the hood. They think if anything was done, it would be blatantly obvious, kinda like going from an Apple IIe to a Mac Pro w/ 2 30" screens. So many people don't understand how important the basic, under the hood infrastructure is.