I have received my Tap 11 and have been playing it for a week now.
Man this is an absolutely gorgeous device! It just grows on me the more I use it. However I very nearly returned it on the first day as the bugginess of the software drivers and the upgrade to Windows 8.1 nearly gave me a brain tumour. I think I got the bugs sorted out now (more on that below).
What I like so far:
(i) the screen size is perfect. I had the Surface Pro and Tap 11 side by side at the store and it was a no brainer. I think the extra inch or so makes a dramatic difference to productivity, and is quite critical if you have aging eyes like me and want to increase the text font to 200% in desktop mode. I also think the extra screen space accomodates the onscreen keyboard better.
(ii) the form factor. I was using it on the train and it was light enough that my hands did not feel tired at all.
(iii) Speed: my Core i5 has not lagged yet, no problems with games and high quality videos so far. The Surface probably has better performance but I think the thickness-performance tradeoff is definitely worth it.
(iv) Kickstand: this is very well designed and built. Yes the Surface kickstand is better but the Vaio's is more sexy
(v) I got a free case from Sony during a local promotion. It fits nicely.
What I don't like:
(i) the speakers are rather average. I think it is not as good as my newish HP laptop with Beats Audio. I don't know how the ipad sounds so can't compare. I wonder if there is a software equaliser that we can download to beef up the bass?? The built in equaliser can only control volume.
(ii) keyboard: I encountered some of the known bugs, e.g. the keyboard locks out if you hold down a key. The only way to fix it is to reset the keyboard by turning it off and connecting it back to the screen, which is quite annoying. I ran into this issue while holding down the down arrow while working on a speadsheet. I think this is probably not critical unless one use it to play action games - that keyboard is really not heavy duty enough for hardcore pressing and pounding anyway... so hardcore games probably need to get another USB keyboard?
(iii) The trackpad is rather over-sensitive as well. Sometimes it goes abit haywire but I wonder if there is some way to adjust trackpad sensitivity in control panel.
(iv) ghost taps registered on screen on areas where I didn't press: this is more an issue when moving the tablet around while using it (or moving around while using the tablet!). I don't get this problem when using it sitting on the table.
(v) bugginess of software drivers: my tap 11 shipped with Windows 8. Windows 8.1 comes as a free upgrade and unfortunately some of Sony's drivers were not fully compatible. After upgrading my screen brightness control simply stopped working, and occasionally i had the start screen default to small tiles. I managed to fix these by turning off automatic screen brightness adjustment and downloading some new drivers.
To summarise: an excellent tablet experience once you get over the initial headaches and learn to work around the bugs!