After the upgrade my battery was going down as I watched it. I fixed that problem by removing some suspect apps (battery monitor, combined battery/sdcard/phone mem widget) and then did the HTC-advised recharge cycle (8hrs phone on, 1hr phone off, 2 min wait, 1hr phone on) and it's worked BRILLIANTY. HIGHLY RECOMMENDED.
After that, I reinstalled the apps and it's all hunky dory... apart from the fact the new USB tethering gets an IP address and doesn't connect to the internet (same for hotspot). I'd guess it's all the same issue ?. A real bummer because when it used to be called "internet sharing" under 2.1 it worked a treat - I even managed run a Citrix session from my office on it
Deffo do the battery cycle thing and remove and re-apply those widgets. It makes a world of difference. I couldn't believe it myself...