Is it worth changing motherboard for HTC One M8 ?

[AC Question]

My Phone stopped working all of a sudden. I had it diagnosed at a local repair store and he mentioned the motherboard is gone. I've sent the phone to HTC Service Center. I'm awaiting for the quote. Do you guys know how much they might quote ? Is it worth changing it ? Please note that I ran out of One year Warranty 6 months back. I love the phone but motherboard failing after just 1.5 years sucks, considering I bought it for $640.