I'm giving this UI a try because i like the concept, the compactness and the use of clear windows. It certainly doesn't add any extra lag, and perhaps it has reduced it as intended, though i hardly ever have lag anyways
A few suggestions though, if I may:
You've gone the unequal in size target/player bar route, which is fine although there's one small thing u could do to make the group and self health bars easier to eyeball quickly. I would suggest that you put the 'F' keys before the health bars instead of between the bar and %. It would make things line up a little better I think.
I like how you've arranged the stats but, and correct me if I've missed it, but the Attack number is missing. This is important to me as a monk so if it was left out either on purpose or in error, bring it back please
!
There is a blank space where the mana bar would be since i play a pure melee character. Perhaps place a stamina bar there for those of us without mana.
And lastly (I think lol) is the timer. I'm not sure what to think about it as of yet, it's not of any real use to me in it's present form but it's probably something I could mess with so I'm not worried about it. However, the red box indicating that attack is on is out of place in this window. Again, from a melee perspective, I sometimes need that surefire indication that attack is really on or off, and having to look at that tiny window is a pain. Perhpas see how it looks when placed around the target window or even the Qbox.
Ok done with the criticizm
great UI, nice to see some good, original ones still being made.
Regards,