I have been fiddling with the tablet some more now. Nothing that would redeem it, but here are some more comments.
Constant crashes. Apparently half of the software on the tablet is faulty. Most of the stuff works fine as long as you don't really do anything with it, but I can average approximately four crashes per extended use session now. The worst offenders are the builtin web browser and the Firefox browser, which seem to crash and close down all the time. God forbid you would consider using Flash - then you are headed for an instant forced close of the application. I have managed to crash the integrated Gallery application, Android's own YouTube application (though for some reason I think this might be related to YT updating their technology over the last few weeks). I even managed to somehow crash the integrated IR remote application.
Unexplained reboots. Every now and then I have been getting reboots with no explanation whatsoever. What's even weirder - most of the time they happen so fast, I cannot even deduce what the reason might be. And the reboots are fucking long.
Extremely unresponsive applications. This bugs the living bejesus out of me. Firefox, which is one of my most used applications on PC, is so god damn slow on the Android, it makes me pull my hair out. First of all, half the time I cannot understand whether the application registers a touch or not. Zooming by pinching is so dodgy, I wish I could disable it altogether. There are some technical issues with the tablet browsers beside that. For example, tiered menus simply do not work. There are severe issues with resizing some web pages, even relatively simple ones. Sometimes I get artifacts on the screen instead of images (garbled colors). When I refresh, they disappear.
All other applications suffer from slow performance - whenever I touch something, there is either a very small pause or a somewhat longer pause. There really is no application that feels like my commands are instantly registered like they are on iPad. Whenever text input is required, the first few button presses seem to be a hit and a miss. Plus the ultra-sensitive screen means that sometimes it registers multiple presses of the same virtual button.
There are other issues, that are apparently Android at its worst. First, you cannot set a normal wallpaper. No, you need a separate application that actually does not work with tablets yet.
I finally found a very nice little file transfer application called File Expert, of course it is designed for phones, but it works just as fine. Plus it allows me to connect to a regular Samba shared file server.
So yeah, there have been many instances where I have felt like smashing the damn thing against the side of a sink or toss it out the window.
TLDR: One day this fance little 500 alarm clock managed to somehow crash its integrated Clock application and my alarm did not sound. I barely managed to get to the office in time for a meeting. Do not buy the Sony Tablet S.