One thing that I really miss when running apps in the modern UI is having the time displayed on the screen. Now I no longer have a quick and convenient way to monitor the time while using the SP3. It's a small thing, I know, but it sure does change the experience, and not for the better, from what has always been there for years and years. I also miss not being able to monitor any aspects of the system, such as CPU load, battery status, and whatnot. I know that I can swipe to open the charms menu and get some of this information, but it is an extra step that detracts from what I'm doing. <Sigh>... well, that progress, I guess.