How does it handle content (movies, games, pc input )?
How's the os?
Are you impressed with it? Is it worth the money?
Does the absence of hdr hurt it by a great deal?
Great questions as these were all the things I was testing.
The OS is snappy and easy to us, but a bit ugly (very window'sy look to it). Overall it was the thing I was least concerned about. All the calibration options you want are in there and was more than happy with the options given. I did not care to test apps.
I was honestly very impressed with it given I had a 9500 right next to it. While their were contrast and some "punchiness" differences even after I had them as balanced as I could make them, the differences were minor in a dimmed room. In a dark room things got worse, but if you can control your lighting the black levels arent near as bad as cheaper screens.. Colors were beautiful, and the screen had a very uniform look to it. Grey patters looked super smooth on it. Considering the price difference compared to the 9500 I felt it was a huge bargin. I originally was comparing it to a 70" Vizio for reference, and it blew it out of the water, with the single exception of black level (surprisingly the vizio looked about as good as the 9500 in this regard... pitty its color handling and overall lack of punch kills it, I blame the non-gloss screen). I care alot about black levels (but not enough to buy an OLED yet, as they have other crippling issues that annoy me beyond belief, and Plasmas were never an option for me due to how often I use my screen as a studio monitor for editing)
The absence of HDR is the exact reason I did not buy it (and in the same breath, the lack of local dimming which kills it for me regarding regular non-hdr content, I can live with LCD's black level when using local diming to midigate it some). I sadly had no content to test with so I could not see any comparisons. I've seen HDR demos already though and know its the next "IT" factor for TV's, I wont buy one without it.
So overall, I think its a beautiful screen thats great for a good room with medium lighting. I think you'll be disappointed if you want a screen that will shine in darkness. Also dont buy if you at all care about HDR. I'd consider it a "2 year" screen, meaning if you bought it, buy it to hold you over for 2 years for, as by then some awesome HDR screens will be out.
Edit: forgot about the first question! It handled games great, I do not know the input lag figured but it felt good to me, responsive with no visable delays. Movies (Pirates: World ends) looked great, 24fps was handled correctly and I did not detect any artificial judder. I honestly like putting Samsung screens on "low" for their motion estimators to get rid of the inherent 24fps judder on pans without killing the rest of the film look, and all the screens did perfect at this (another area vizio fell on its face on).
Of all the screens I had in front of me, I'd take Samsungs current line up followed closely by Sony. Sharp, LG and Vizio all were in a tier lower.