I agree with the other poster. RIDE BIKES and then RE-RIDE BIKES. And don't accept short rides but ask for additional time. Also try finding bumpy or chip-sealed pavement if you are looking to see how "comfortable" a bike feels.

I managed to get in some testing in late Sept, early Oct between rain showers to test and, again RE-test some rides and even the same bike in different sizes. I was lucky in that some of the local shops had a variety of brands. I concentrated on 3 different shops with mixed brands and sizes. And I hopped from one bike to another pretty quickly so that I could compare the rides doing the same pavement and hills. I believe that I was able to discern differences in the rides of the various bikes.

Good luck finding something you like.