Diamondback Sorrento for first starter bike?
You're an exceptionally experienced programmer, you know by now that life is a series of compromises and trade offs. Yes the diamondback is a good bike for that price, but you get what you pay for. If you really want a bicycle you'll enjoy, go to a family owned local bike shop and trade a little extra money for an experienced employee to fit you to a bike that's just right for you.