I made the switch yesterday from MythTV, and I'm impressed with the look and WAF of Channels. While I was recreating all of our series passes from Myth, I noticed the "Limit" dropdown is only in the Advanced setting, while the "All episodes" choice is only on the standard pass creation menu.
For example, I want to keep 10 episodes of Mythbusters on hand. Since it's a canceled show, I have to create the pass from the standard window so that I can select "All Episodes," otherwise nothing will ever record. After creating the pass, I have to navigate to DVR > Passes, find the show in the ever growing list of passes, click the down arrow, choose advanced, select Limit 10.
It seems like there's plenty of real estate to add the Limit dropdown to the standard series pass creation dialogue, and that would greatly reduce the amount of clicks required to establish a pass with a limit.
Incidentally, I'm making sure to limit most passes since Channels can't automatically record to multiple storage locations. I'm gone for long periods of time and don't want to get caught out of space while I'm unable to move things around on the storage drives. We tend to keep a bunch of shows on hand, some for family viewing, some kids only, some adults only, and a few just for my wife or me.