I too thought the big tiles would make for a perfect Media Centre Interface. I upgraded on Day 1 full of enthusiasm and almost no concern about its special new interface.
I installed everything I needed including Sickbeard, SABnzbd, Wild Media Server and XBMC, but soon discovered there was no way to make the big tiles look pretty. I thought I would be able to resize and change the appearance. Maybe there will be an app for this one day.
Strangely I wanted my desktop to stay in Tikfam mode, but because XBMC is a desktop application that is where it opens and when it closes it stays in desktop. That means I now have to either put shortcuts on the desktop or bounce back to Tikfam with the special mouse fling each time to launch something which rather defeats its intended purpose. I wanted to avoid using the keyboard.
Ok, no insurmountable issues yet and carrying on.
I only used a 40GB partition as I did not intend to install anything other than a few apps, but now I am running out of space. It turns out that where Windows 7 used a 3GB page file, Windows 8 is using 12GB on the exact same machine. A swift change and reboot fixes this.
I always have my low power HTPC on and when I returned to it a few days later I find that runtime broker is using 90% of the RAM and terminating programs left and right without asking. A bit of investigating and I find it is a new Windows 8 bug and is fixed by uninstalling an affected program.
Still trying, after all I persisted for almost a year with Vista.
Tried to link up to my Pi box. Still no NFS server in Windows 8 Pro so I have to use SMB. The email account I used to login does not work nicely with shares so I have to change it to a local account. Changing this should be easy, but the user admin stuff is split between Tikfam and Desktop. Very irritating.
Everything is now setup, but it doesn't seem faster, spends most of the time in desktop and I can't help feeling that at any minute Tikfam will do something annoying. I defaulted the dual boot back to 7 and haven't touched 8 in 2 weeks.
My personal verdict is that it offers no advantage at all over 7 and many ugly problems. Will retry maybe after SP1.