I would ride one man, if you really want CF. But, you can get an awesome trek emonda ALR/CAAD12 in that price range if you find a deal, which it what I would take, personally.

I've smoked riders uphill on a $230 nashbar bike vs their carbon bikes (starting to sound like durian rider lol). Man thing about bikes isn't the materials, its the feel and fit, for you! Its all about how much you enjoy it and fitness level will get you faster.

Yes, tektro brakes are trash. Swap those out asap.

tl;dr wouldn't hesitiate to ride a CF nashbar bike, I have their flat bar disc bike for commuting and it has been great. But, you can probably get a nice feeling/lighter aliminum frame for that price. I do believe the nashbar CF bikes come in at 19lbs. Not bad, but you can get a diamonback podium with some 105 and HED wheels (I think even full carbon fork/seatpost) that comes in at 16.5lbs for that price at discount. Or an emonda/caad at 18lbs