I'd think about cost versus price.
If you're a new rider, the bet here is you're going to find the LBS (assuming they are friendly and well established) is a better value in the long run - in fact you're already seeing it in the ability to get a test ride - which is free at the LBS and Diamondback can't provide at any cost. You're not getting a deal on the Diamondback versus "no deal" on the Fuji really - that corporate discount is so widely available that it's basically their default retail.
Now, all that said it sounds like I might be rooting against the Diamondback which would be wrong. They build solid bikes. Personally, I find the branding is a little over the top on some frames but generally the component sets are good value for the money. I have two friends that own different grades of the Haanjo and they love them. On the other hand, they both are also completely comfortable wrenching on their bikes - if you're not, that's something to consider.
Good luck with your choice - the best thing about an entry level bike is it will help you learn what you really like... so sooner or later you'll be looking to trade-up or join the N+1 crowd...
Good luck with your decision.