In my old job it worked well yet, it was a small company at the most around 20,000 emails in 24 hours. With my new job 200,000 day it doesn't work well. Me and my coworker did some testing some things to know:
Time filter searches start from the end and go to start. Example: Want emails from 10:00 AM to 12:00 PM It will get all the 12:00PM emails first. If you add time with any other filter will start looking at 12:00 PM and go back.
There is some time limit or message limit that has been placed on the search. It seems now like 4 min at the most or message limit. I don't think it used to have this as I had my barracuda search before for a good 10 min or more or just "hose up" I think if I waited it would give me the results I wanted. My co-worker also contacted support and said that we needed to be more exact in our message searching. But when you are looking for a subject because it is phishing users.