It depends a lot on your eyes. Some people have trouble reading for extended periods on an LCD screen. Does the iPad bother you when reading for extended periods? If so you might have that problem with the KFire too, although the screen and text rendering on the KFire are probably going to be much better than they are on the iPad, at least in terms of reading. IPads are notorious for their fuzzy text--I've got one and I can confirm that text rendered on an iPad is really crappy compared to say a NookColor.
Another issue you mentioned is weight. Although lighter than the iPad 1, the KFire is still close to a pound, and that might still be too heavy for you.
You also mentioned reading outside. I don't think any LCD device can do that well. Some claim they can, but my experience is that they will be overcome with glare from sunlight. When it comes to reading in sunlight, E Ink devices rule.
Last edited by jswinden; 11-13-2011 at 01:32 PM.