I didn't really time it either. I checked the time I just started another upgrade. Will see how long it takes.
UPDATE: Going from 11.2 to 11.4 took about 40 minutes on my hardware. Doing 11.3 to 11.4 now...
UPDATE2: Going from 11.3 to 11.4 took a lot less time, like 15min. I suspect it not only matters the major release, but the sub-release (e.g. 11.2-RELEASE-p12 will take less time than 11.2-RELEASE-p9 since it is 3 patch releases newer and thus fewer files to patch.
Also, any known issues with updating iocage jails containing OpenVPN, Plex, Apache, etc.?