I am on the road in Rajasthan, India. And I am making heavy use of my iPhone4. I am surfing, writing emails, taking and modifying pictures, blogging. I have an indian SIM from Airtel, 2gb data in 30 days for 10 Rupies (about 0,16 € 🙂
The network coverage is excellent. You only have Edge to surf, no 3G network. But hey, long car rides and enough time to wait for a page to load.
With a 100% battery charge in the morning I work it down to 40% in the evening, and that is very heavy use. With moderate use I could go towards 2 days without recharging.
These are normal use times for the iPhone4 as I have read them from other user reports.