I can't speak for Richard Gere, but several things appealing about Tibetan Buddhism off the bat:
1. It has a highly developed, rigorous, and subtle psychological system which bespeaks some very powerful and wise minds in its construction, while also leaving plenty of room for mystical experience.
2. It has beautiful liturgy, art, music, etc.
3. It is an ancient and deep-rooted tradition with strong monastic as well as lay foundations.
4. A lot of the monks/ nuns you'll meet seem like genuinely kind, caring, and thoughtful people.