Everyone always says to go for a test ride - what do you learn on a test ride, truly? That you don't hate the bike. OK it's good to eliminate that, but beyond this?
Comfort is so dependent on set up, handling is dependent on ability and confidence to push hard - not really what happens on test rides. I am not advocating against test rides, but I do have to question it when people say that they are ''essential''. I learn more about a bike from a good review, and a look at the bike's geometry than I do from a brief test ride. It takes me much longer to evaluate a bike just on 'how it rides' than one short ride.
Combine the above with other real world factors, such as time constraints, bike availability in the right size, LBS willingness, and I wonder how many new bike purchases are actually decided (and decided 'correctly') on test rides. None of the 5 I've bought.