Re: what 4K monitor are you using?
 

I'm using an LG 27UD60-B for my main computer monitor. The switch from a regular HD monitor took a little getting used to, but I'm okay with it now. I edit 4k in Premiere Pro CC with a Vizio M43-C1 4k TV as my timeline monitor. Yes, it's a TV, but that's what I'm shooting for -- not broadcast -- so it works well for me.

(I shoot almost exclusively in 4K using a Sony AX100, a Mavic Pro drone, and sometimes a Yi 4K+ action camera for GoPro-type footage.)