Personally, I feel like 5k miles is a little short of what I'd expect for a 2.5 hour mechanical... although I'd find the miles more useful than a free ticket voucher (if that's what the other option was, and not like a $25 CS cert)

I never see UX give these out ... I've had a flight come in and announce, "The lav on the plane is out of order; if you need to go, we suggest you visit the terminal restrooms now." Also plenty of other mechanical delays there, too... wonder if the CS certs are basically handed out only by mainline UA?