Although I have never met Fr Miller, my brother and his family have been members of his mission in AL for many years, and are very fond of him. Additionally, my brother in law and his family have been members of a mission of his in TX for many years, and they also have always spoken very highly of him. As mentioned by Lad, he is one of the most solid of the many branches of the Thuc tree, and has a long history of public service during the crisis that, to my knowledge, has been free from controversy (which is sadly rare in traddyland). If I had an opportunity to attend one of his masses, I would not hesitate.