Generally a thread of blech, but to go back and throw my 0.02 in on the OP -

1. They probably said this because of the number of broken Rival shift levers that they have seen. It happens. I have seen my fair share too. In my experience it seems to be how the rear derail is setup and has more to do with their wrenching ability than the rider's weight. Saying 105 is more durable that Rival...stretch to be sure, but it doesn't have anything to do with rider weight.

2. Trek bikes sell for more than the value I feel they represent. I'll buy them a beer on that one. The research bit is BS.

3. Giant is one of the best values out there. No soup for them.

4. Who cares. Fit is most important. Regardless of whether they spend hours fitting you or you spend hours riding the rig as a test ride....it's your first "real" road bike. You'll know what to look for when it comes time to get you "second" real road bike. Basically if it reasonably seems to fit (based on your limited experience), you like the bike, and it represents a value equal or higher than the price they are willing to sll it to you for then buy it, ride it and enjoy it.

.....this isn't a debate about politics, world hunger or world peace. It's talking about buying a bike. To ride. To have fun. So....buy the one that's fun for you.