Overall performances seems to have taken a hit, especially when mass editing though I am amazed how well performance is when stitching panoramic shots. I see this more while say exporting a large group of images and continuing to work on additional images getting them ready to export.
The biggest issue is using the edit feature to open in PS. The first time with PS closed, the entire process times out and when PS opens there is no image that has been exported. If I re-attempt to edit in PS through LR, 2 image tabs with the same image open in LR. Not a show stopper but certainly not desirable. This has been happening since the last 2 upgrade releases of both PS and LR.
Start up speed for both LR and PS is perhaps the second biggest issue. LR is very slow to start taking sometimes 2 minutes to fully be up and running...in spite of my system exceeding the software requirements. (WIN 10, Icor7 with 16gb RAM should be more than enough.