I’ve used CM a few times this season. I find the term “slow auction” a little misleading because there’s a lot of activity that goes on- or that can go on.
The slow auction is entirely customizable. My drafts started with a 12 hour nomination start timer, and an 8- or 10 hour reset when the bids were upped after the timer drops below that window. Each team started with 2 nominations and we upped that number when the league was comfortable. In a 16-team league, we had 3 noms per team and a total of 48 going after the first four days. It was pretty manageable for all teams involved. CM admins are quick to respond to questions/comments/emails and requests for players to be added to the universe.
My experience has been positive overall.