As said earlier, Fr. Hampsch is in good standing with his order and the Church, and, furthermore, is a great man. You can truly feel the joy and love of his spirit in the room, and, even if you are not inclined to believe in the nature of some of his works, I highly recommend attending his Mass and services - you will be enriched for it.
While by post-Vatican Council II standards, some of his blessings and rituals seem a bit archaic, they are still a huge value and when they are forgotten, they will be a sad loss. Unlike some others who are keeping some of the older rituals alive, Fr. Hampsch is very respectful of the work and progress made by Vatican Council II.
Some of his reading materials seem a bit simplistic, but he is addressing emotive issues, and simplicity may be the best way to access the majority of people. Other works are quite scholarly and require a strong foundation in the Catholic catechism, history and tradition. In any case, it is well worth the read and is in absolutely no way heretical.