One of my recent submissions has been out for a while and thought I would get the exact number.
You can use this to calculate business days(I checked marked the option to count the last day)
For me
Longest - 113 business days and counting
Shortest - 2 business days
Shortest bulk submission - 4 business days (56 cards)
Shortest - 2 hours (1 card in person at Nationals for $125)
Longest - roughly 3.5 months a couple times. One was in 2014 (Early May to August) & this past year during the June bulk submissions. One came back late October.
Some of these seem longer because PSA would take 2-3 weeks to put an order in the system.