The viewing angles offered by the 27UL550 are typical for mid range and high end AHVA/IPS/PLS panel, which means that they're wider and far less restrictive than TN and VA panels when viewing colors and not viewing content with lots of black and dark grey shades. The 27UL550 has wider viewing angles and suffers from less glow than my Acer H257HU (1440p AH-IPS), ViewSonic VP2780-4K (4K LG AH-IPS), and gloss X-Star DP2710 (1440p Samsung PLS), as well as is almost on par with the low glow 32" 4K AUO AHVA panels and the low glow AHVA panel in the Monoprice 274K or RTD2795 I tested in 2017, so I consider it to be an above average and high end AHVA/IPS/PLS panel glow and viewing angle wise.
LG 27UL550 Viewing Angle 1 LG 27UL550 Viewing Angle 2 LG 27UL550 Viewing Angle 3 LG 27UL550 Viewing Angle 4