I don't have a 44 mag, so no first hand experience.
IIRC, there were several feedbacks at midwayusa on red-dots that folks put on 44s. Might be a good place to look at prices and owner feedback.
I have bought several of the Millett red-dots and have been very happy with them. They are all on hard recoiling guns (not 44s, though), and none have any problems holding zero. Am fixing to order another soon.