I have never had an issue with HP support. We have 4 hour response time support and if you provide your information correctly (SN, part #, etc) you get your issues resolved in no time.
We had a failed disk tray and after spending 15min on the phone, providing the contract numbers, part # and SN; we had our replacement unit within 3 hours.
Impressive, considering the hardware is from 2005 and has been discontinued for a long time.
Not in the grand scheme of things. We've had similar service from Dell; one instance in particular involved a warranty-replacement riser card for a PE2900 or 2950. It arrived while we were still onsite, so it couldn't have been more than a few hours between us calling Dell and us receiving the part.