Slow as in "useless".

I bought and installed C1 21. I pointed program to my LR catalog and it started to generate previews. 

It takes more than 40 minutes to generate 1000 previews!!!!

I am using or have recently used LR, Exposure X5 and X6 and different versions of ON1, also digikam, darktable, IMatch, Raw Therapee, PSP etc, etc.

Nothing, nothing ever comes even remotely close to that. 40 minutes for 1000 previews!!

So I may use LR and Photoshop and if want to dump them, I may use IMatch and Affinity Photo. 

Those programs work. I can actually _do_ things with them. Instead of waiting and/or fighting bugs.

Bye bye C1.