So I upgraded my MacBook Pro’s OS from Sierra to High Sierra but it wasn’t very nice experience.
The machine was acting sluggish and there were huge memory consumption by different apps. QuickLookUIServer happened to be one of them.
So took 10 GB / 10 GB RAM I had and rest of the processes were running on SWAP space / Cache.
Moreover the sad thing about the High Sierra is that you cannot skim through the videos while previewing in finder. Being a video editing enthusiast, it is such a loss for me in terms of time and everytime I had to open the videos in VLC player to be able to skim through the videos.
So my recommendation is against upgrading to High Sierra.