Best 4K monitor with PBP (Picture-By-Picture)

I'm looking at large 4K monitors (36"+) to be used with a MacBook Pro and additional machines I might be maintaining. So far, I've come across offerings such as the Dell P4317Q, LG 43ud79, Phillips BDM4037UW_27, and ViewSonic VX4380-4K. Since I code and design, I think an IPS display would be ideal. Weigh in! I'd also like to consider PPI for retina use: https://bjango.com/articles/mace...