I'm in an agree-to-disagree state with various sql server consultants on this matter. I disagree that merge is harmful and should be avoided. Using merge w/hints for upserts has a decent performance advantage over the alternatives and comes with some theoretical risk of deadlocks that depend on implementation details of your use case and/or the shape of your data (I've yet to encounter it in practice, I tend to batch upserts and limit concurrency and suspect the folks having trouble do the opposite)