I was checking out the Galaxy S II for AT&T today, and I really did like the form factor and most of the backside. I can live with a 4.3 inch screen. The difference between the height and width of the Captivate vs GSII is hardly noticeable. Only neg is obviously the plastic on the bottom and the borders.
You either pick your poison. Glass, and you feel premium, weight, and that "bling" factor when it is clean. But it shatters and prone to fingerprints. Or plastic where you get that cheap lightweight feel, prone to scratches (and fingerprints), but can take sudden impact a little better since it can bend. And lightweight does help the innards better since gravity loves heavier phones.
For me when it comes to solid construction and better ergonomics, HTC or Motorola FTW! The Sensations, MyTouch Slide 4G, Droid Bionic, Droid RAZR, and even the recent and well-reviewed Nokia N9 look very durable to me.
Lately, I've been craving design. I would go to a store and just check out all the phones and I would feel it in my hand. I don't crave about OSes, apps, or ecosystems right now. Why does the Android phones appeal to me lately than iPhones? Because Android offers variety when it comes to designs and form factors. Seems more interesting. With iPhone, you have to wait about two years just for a NEW design.