I unhooked my Evo at 7:30am today, got into work at 9am, and have had the wifi hotspot on all day, using it tethered to my iPad. I've surfed on and off throughout the day and now at 3:58pm, some 8.5 hours later it at 7%.
I sent a dozen or so texts, had one other salesmen tether for maybe 20 mins to enter an order at work, and have gmail pushing mail all day. I've read some email, checked weather and stocks. I run no widgets other than the HTC clock/weather ones that came stock. I turned off the autoupdates in the system settings on everything but email and twice today I used ATK to shut down background apps.
This coming from yesterday running half a dozen widgets and the battery only making about 4 hours. Turning off the auto updates to crap like facebook and the other Sprint apps and removing widgets made the battery life double even while leaving on the Hotspot feature today. I think people need to do a bit of reading and understand just how much "stuff" their phone is doing before making claims they have a defective phone.
If you just switched from an iPhone there are clearly thing to manage vs the locked down iPhone Eco system. iPhone has good battery life for a reason, no real multitasking.