Nothing wrong with buying a very low priced entry level bike. At that price you are going to have to go with Sora unless you buy used. If I wanted to spend $500ish on a NEW bike I would get the Scott Speedster S60 from REI it's $589 plus you get 10% cash back at the end of the year. It's basically equipped the same as the BD bike but you get a 'professional' assembly and REI has a 100% lifetime satisfaction guarantee on EVERY item.

Scott Speedster S60