When I got back into road cycling after a longish absence I first bought a TCR. Great bike. However, a couple of years later I also bought an SCRC4 (a predecessor to the Defy advanced) because I was doing a lot of long rides and wanted to try the more relaxed geometry. Suffice it to say that I don't use the TCR much. It's still a great bike but I'm not racing crits so its faster handling doesn't matter to me, and it isn't as comfortable when I'm going to be out for 3, 4, 5 hours. For all normal purposes I'm just as fast, and more comfortable, on the SCR.

Just my two cents. As others have said, it's not about the bike, but for a LBS to be encouraging the more aggressive set-up on grounds of comfort is slightly odd, in my opinion.