I am using service #1 with some b'nai mitzvah, though they are leading from a cut-and-pasted version in a binder, making for a "linear" experience. We spend time looking at each double-page spread, choosing the prayer they want to lead, thinking together about the content on each page as well as the balance across the service (Eng/Heb, right/left, read/sung). That learning has been a nice experience, and as long as page numbers are adequately announced and time is given for the turns, our "guests" are doing well during the service too.
BTW, almost a year in now, and both non-linear services are quite well-received by our regulars. Initial griping stopped with more familiarity (and subtle but more frequent page announcements by me).