~500 people.

We have Concur available to us, but no hard requirement to use it to book. I've tested it to see if it yields lower airfares or hotel rates and it actually does the opposite: shows identical airfares as airline websites and hotel sites, but then adds some fee-cramming on top of it. Need to make a change to anything? More fee cramming. So ultimately, few people use it for booking, although we all have to use it for reimbursement.

We tend to pay for ourselves and get reimbursed after the trip, but there is an exception process if the employee requests it for cashflow reasons. For example, if we're sending somebody to India for a week, the airfare can be run through a company credit card. I'm happy to run everything through my various rewards credit cards, but it's nice to have that option there.