That's a perfectly good bike. If you're ok with the mild assembly required of BD and the fact that you may have to take it to an LBS for a initial inspection ($50-100), you're good to go.

Sora's fine. I use it for riding hard - it's not perfect, but it's the last thing that's slowing me down. When well adjusted, it will perform excellently unless you're intentionally shifting it under really high loads.

You can win TTs and races with that bike - no joke. Despite what all the haters say, if that bike fits you correctly and is assembled properly, it will be 97+% as fast as the $5k Dura-Ace Cervelo in your LBS. I ride a nearly identically spec'd bike (from LBS, but is Sora and entry level) and I do a bike shop ride where most of the bikes in the group are north of $3k, and can confirm that the bike is definitely NOT holding me back.