Ok, you have a LBS that will work with you, that's great. Now step back a moment. You started at a $400 level and now are looking at $650 bikes. You said sometimes you get buyer's remorse, right? With a true entry level bike, it will be more prone to problems than a good starter bike. I was at the same crossroads not too long ago. I decided to set my purchase point for good starter bike at $1,000. I looked and rode bikes at my target +/- $300. That really helped. What helped even more was to come back another day for a short ride of the bikes I liked the first go around. That second ride was the telling ride. Several at the top of my list, disappeared. I ended up with a $1,200 bike and never regretted it. Because I spent over $1k, I had to validate my purchase and had to go riding more. I would have just p***d off the $500 bike and would be sitting in the garage.
The only "bad news" about cycling, is I am enjoying it too much. I'm planning on adding 3 hours sat am group rides and buying another bike. This time it will be a great bike, with cyclesdales wheels, a more rider friendly frame, and easier to pedal in the wind. It'll be like buying an old used car, so it's budgeted for next year. [You don't want to know how much.] But putting a bundle on a used car bike is a lot better than buying a pace maker and medical supplies.