Wow.

1-3 they are completely full of crap.

#4, I actually agree with them, but I agree with you too. You'd think they would want you to test it and fall in love, it's neither here nor there though.

All of those bikes are going to rock your world. 105 is awesome. Rival is awesome. Get the one you feel is right for you and go from there. The last thing I'd trust these guys with is them fitting you to a bike. I'd be inclined to think they tell you that you fit great on one because they want it out of the door, and I bet your ass it's going to be a Tarmac, with 105 on it. I would imagine because it's marginally more expensive (or in stock).