I've had a Seiki 40 inch 4K monitor for about a year now, and its incredible:
https://www.amazon.com/Seiki-SM40UNP-40-0-Inch-LED-Lit-Monitor/dp/B00RVGXZ08/ref=sr_1_2?s=pc&ie=UTF8&qid=1480238156&sr=1-2&keywords=SEIKI+4K+MONITOR