First, they all have super-fast internal processors. Whether you've got the A4 or the Snapdragon, you're going to have a very fast smartphone.
- Droid Incredible: Very fast, still using the 3G Verizon Wireless network, allows tethering (including Wi-Fi hotspot), great camera, and runs Android. Expandable memory (up to 32GB microSD) and you can remove the battery.
- Apple iPhone 4: Still using a 3G network, great design, only on AT&T, video conferencing appears to be limited to Wi-Fi for now so that front-facing camera may not be that useful, and AT&T to offer tethering sometime in the future (when?). Can't expand the memory or change the battery yourself. How will AT&T's network improve? Will we continue to see all those dropped calls?
- HTC Evo 4G: First (and currently the only) smartphone on a 4G network. Limited to the Sprint network (which is currently the only 4G network). Very large screen and running the Android OS. Expandable memory (up to 32GB microSD) and you can remove the battery.
If you want the fastest smartphone with 4G data speeds, then the Evo 4G is your clear answer. However, if you want to stay current on the Apple iPhone OS which currently offers the widest selection of medical apps, then go with the new iPhone 4. The Droid Incredible is a great phone for Verizon customers and the Verizon Wireless network has been rated as one of the best wireless networks in America. My family has been with Verizon for over 10 years and we've been happy with their coverage. If coverage is important, then go with Verizon.