I have had my G1 for 14 months. October 2008.

There has always been an onscreen keyboard along with the slide out keyboard.

I have not had any battery issues. I do keep GPS off unless I need it. I keep screen at 50%. No need for it to be brighter. My 3G is always on except when using WiFi at home.

On a performance note. I rooted my G1 during the summer. I have compared it to Touch's and Hero's and its faster than their stock phones.

 

yes, android 1.5 ha added an onscreen keyboard.
battery life may also be a little better, but not by much.
I've found some extended batteries that don't require larger backs for about $10, although I haven't actually got one yet so I can't say if they're much better or not

 

well a couple of things. if you get a g1 now instead of a material finish its glossy. also it comes with a 3.5 mm headphone and comes with a mini usb ext adapter. the accessories will always be black regardless of what color you get it. otherwise no battery upgrades.