I've been using Lightroom since the first version up to LR6. I've tried On1 Photo Raw 2019.5 but it's not a LR replacement, yet. The two key features that keep me from leaving LR is:
1. The export dialog with ease of selecting presets, but then i am able to quickly change a destination if needed. On1 doesn't start at the current selected directory so you have to re-navigate again to where you want to save to. It's these little things that make On1 frustrating to use.
2. Being able to right click on an image(s) and edit in external program like Photoshop Affinity Photo no matter what