I find the SLOWEST non-CLEAR security lines to be at terminals that are run by a single airline with a financial interest in encouraging on-site CLEAR sign-ups. The worst I've seen is LGA Terminal C, which is run by DL. A couple years ago I was dropping off an unaccompanied minor and thus had to use the general security line, and I was in line for a full 45 minutes, while there was NOBODY in either of the CLEAR lines (CLEAR with or without precheck). I didn't see the non-CLEAR precheck line, but assume it was longer than CLEAR and shorter than general.

CLEAR workers were trolling the general line offering free trials of CLEAR that would allow people to skip the general queue. A DL employee was offering zero help to those about to miss their flights ("if you miss your flight we'll try to rebook you"), except to suggest that they sign up for CLEAR. Lots of folks signed up for CLEAR that day, and I'm sure DL got a nice cut of it.