But LU, when it works, is less flops (only half though, IIRC). And doesn't require a square-root. I think that's why it used to be preferred when compute was a

But LU, when it works, is less flops (only half though, IIRC). And doesn't require a square-root. I think that's why it used to be preferred when compute was a very scarce resource. Clearly that's not really the case anymore today. But otherwise I agree, QR is almost better on every front.