Dang. My Dad's not exactly smartphone savvy "there's Wi-Fi on this?" but seems to do just fine with it....beside's the battery life. It's just woefully, unacceptably, bad. My phone's able to last a day and a half with moderate use, that's with it overclocked and undervolted.
I will agree that the Galaxy S was flawed from the start. Rooted and with RFS removed, it's a screamer of a phone, however most people expect a great device out of the box, as it should be.
I've had the touchscreen issue with the "incoming call" screen but that's because I'm running custom rom's and stuff. I never experienced it on my phone running stock Android that was pushed to the device. I should note that, on MIUI, I haven't had this issue so far...but i'm having other issues like the phone losing responsiveness overtime that has never occurred on another rom. It's a shame because this ROM is one of the smoothest, most refined Android experiences I've used. Sure it's iOSesque if you dont theme it, but you really feel like the details have truly been sweated, from the widget adding process, to the kinetic scrolling.