May 2013 - I just bought the HOX as my upgrade phone over the SGS3 because I've been using HTC for the past 4 years and grew accustomed to sense. I have the same problem with the sluggish scrolling of screens in Sense. When I turn the "block"/page/screen, the edges of the images are choppy and the motion of turning looks like it goes from 30 fps (or whatever it actually is, maybe 24) to 20. I have read all the posts and I appreciate that people are trying to find a solution but I'd like to add that HTC should be shameful of releasing a product that has a known issue. HTC would rather meet a deadline over providing a reliable product, take our money and ignore the issue after they've gotten paid.
Anyway, it seems like Yahoo Mail and especially apps that require location services greatly consume memory are the ones to blame. While I have that Yahoo Mail installed, I have to restart the device almost everyday just to get the smoothness back. The phone itself is fast if certain apps are not installed and I do recall that the interface was very smooth in the beginning, but like most veteran mobile users, I use only specific apps on my phone and install them all at once. In fact, switching from phone to phone is no big deal since my contacts are all saved through GMail and my apps are the following:
Gmail
YMail
Square
PayPal Here
SncMe
Skype
Chrome
Wolfram Alpha
eBay
Android Assistant
Wells Fargo
Sound Hound
Shazam
YouTube
My solution for the lag was a hard reset....but every day!