I have to admit that I've been very impressed by the HTC ThunderBolt 4G on Verizon. Compared to my old Motorola Droid X (which is a fine smartphone), the ThunderBolt feels so much faster and the 4G speeds are great for bloggers who like to upload photos and videos when they're at a conference or meeting. The WiFi Mobile Hotspot also works reliably.
For me, the biggest disappointment is the battery life on the HTC ThunderBolt. I may need to invest in an extended battery (which would make the phone really bulky) and use that battery when I know I'll require all-day performance.
It's refreshing to use a smartphone that's fast and responsive. I hope to share more as I continue to use this device.