With Sharp no longer in the business we have to go elsewhere. Panasonic make the most reliable TVs, but their 4k are expensive. A Vierra 1080p would fit your budget. My second bet would be Sony and they have a 4k 55" right around the $800 mark.
Samsung and LG are the 2 mass market Korean sets. They seem nice but I don't trust their reliability. I've had so much rotten luck with Samsung and LG electronics that I quit buying them. Just like Hyundai. They try to offer a lot for your money and advertise how nice they're things are compared to the competition which is true. Hyundai does have a nice car for the money compared to Honda, but that's while it's sitting on the lot brand new. 6 years later and the Honda is still like...