Yes these do make a big difference!
After spending 6 months off the bike recovering from a herniated disc in my lower back, a friend recommended that I try latex tubes to soften up the ride. I thought he was crazy because there's no way a tube can make a difference in the ride quality, right? I was surely wrong because I could tell on my maiden voyage with the latex tubes the significant improvement! For one, the latex tubes feel as if they do a better job absorbing road vibrations. Secondly, and this could be my imagination, but there seemed to be a decrease in rolling resistance as well. Yes, it's true that you have to fill these up with air before every ride, which probably negates the benefit to my back, but overall this an inexpensive and great upgrade for your bike. I also rode with the same pair of tubes from August to December and did not get one flat (~1,500 miles). Bottom line is these are highly recommended and should be standard on everyone's bikes!