Their service plans are great. I've used them many times. They'll swap out items no questions asked. Already replaced two iPads that the kids broke. Brought in the broken ones and they gave me new ones (refurbished, of course).
I like Best Buy a lot and am typing this reply on a Samsung Chromebook I picked up at the local BB just yesterday for the same price as Amazon was selling them for. It'll be a sad day when BB closes their doors. I think one of their problems is there is just too many of them.
I've had just the opposite experience, but that was quite a while ago. Back in the old days of VCRs I bought a plan mainly because it included free cleaning. I dropped off a VCR and nearly a week later it hadn't been touched yet. So I brought in my service contract which had the cancellation terms on it and told the manager I wanted my VCR back immediately, was cancelling the contract and wanted a pro rated refund as specified. I have never seen people there move so fast because the manager did not want a cancellation on his record. The VCR was cleaned in fifteen minutes and he gave me a gift card for the full amount of the contract (not pro rated) and let me keep the contract. I never got another service contract there again.