Mark B. of the Diehard Gamer recently reviewed both Do: Pilgrims of the Flying Temple and Do: The Book of Letters. Spoiler alert! He quite likes them both.
On Do: Pilgrims of the Flying Temple: "If you’re looking for a simple RPG to have fun with, or a game to introduce someone to the idea of RPG’s without scaring them off, Do: Pilgrims of the Flying Temple is a fun, low-maintenance RPG ... it’s a lot of fun to play whether you’re a multi-year veteran or you’ve never played an RPG in your life, regardless of how old you are. "
On Do: The Book of Letters: "As an addition to Do: Pilgrims of the Flying Temple, it’s a fine one, both due to its inexpensive price and the volume of content included in the book for running and creating new letters for your pilgrims."