I recently used concur, and by 'used' I mean I clicked to a page that said "our servers are down" and then I called the travel agent directly who then booked my travel over the phone.

Of dear God, I had to use Concur at a previous job. What a nightmare.

I think concur depends on the implementation - at one job I had to fax in receipts and was painful, at another they had an email gateway configured where you just took a photo of the receipt and emailed it, and it did OCR and imported all the receipts automatically.

concur isn't that terrible, at least I had no trouble using it