Good point, a conflict avoidant part of me has surfaced it seemsI personally wouldn't use this phrasing, as it reads as though something bad has happened, which it hasn't, you just preferred the other company. I would be honest and say that you received another offer, which you've accepted, thanks for the opportunity... - I wouldn't say, "so sorry to mess you around" either, even if you feel that way, it's better to keep a professional and less personal front!
Does it still sound good if I drop the second sentence and don't add anything else?