Update
So we have had the TV now for some 14 weeks or so, and do I miss the GT50...?
In one word, no!
The F8000 continues to impress on every level, and long gone are the days of DSE, blurring fast motion and image retention
One of the most impressive features of the Samsung is the Plex app.
I'd been using DLNA on the GT50, with Plex Media Server on my Mbpr, but to be honest, it really struggled, and picture quality was sometimes poor
With the proper Plex interface on the F8000 my media library is easily accessed, runs responsively and the PQ is fantastic
In summary, a great TV, and highly recommended.
I realise that the F8000 is now obsolete, but from what I can see, the new H7000 is about as close as you will get now (TV even looks identical, bar the stand...) but there may still be F8000's out there at reduced prices