Anyone that owns a smartphone, knows that battery life isn't a real strong point, including the iPhone. "sluggish response"? Are you sure you were using the EVO 4g? It's anything but sluggish. Questionable build quality? Strange to say the least, most sites and smartphone users would say just the opposite when it comes to HTC. That's usually a comment you see associated with Samsung phones. But everyone is entitled to their opinion.
Good luck with your Charge though, seems like a decent phone.
With the same usage patterns, my iPhone would be around 70% when I got home from work whereas my Evo couldn't even make it to lunch before it would drop below 70%, 4g disabled. Sense was very slow and web browsing excruciating with the freezes and hiccups. But iOS blows in so many ways. Lots of tradeoffs either way you go, IMHO.