UPS is the devil. A vast majority of what has been mailed to me via UPS has been damaged. It's impossible the file an insurance claim with them and I think the last time we did file one they never did refund us for the damaged material. The last package I got from them for my motorcycle jacket was so crushed that the box was physically open... yea I refuse to ship UPS.
I love USPS... that flat rate box is amazing, I've never had an issue with regular US Postal Service