HTC Chacha is a QWERTY phone with only 2.6" screen with HVGA resolution...
You truely want to browse the web well and use document features? Don't look past Motorola Defy. Everyone on this forum suggests that phone because it is value for money...
Every phone these days comes with a document reader. That shouldn't be a concern. But if you want a rich browsing experience then getting a big screen is better than to stick with a qwerty pad. Like the defy suggested above will be miles ahead in browsing experience than the other phones you have in mind.
compare mobile to mobile, not mobile to tablets. check your usage & decide accordingly what you want. a 7" bulky device or a 3.7" solidly built smartphone.
but moto defy has better resoultion and same OS , so big screen tab (low end) cant beat a Good smart phone, i think so. what is your opinion about that