What products has John Maeda designed that we can use or have used in the past?
Writing books is great, but its the practical application that really builds reputations.
I would rather not show you specific examples and risk generalizing his work, but I don't want to drown your interest under perhaps too many choices, so I suppose I would point to his different advertisement pieces for Shiseido (interactive and print) as an introduction. (Search for images with the terms John Maeda Shiseido and crawl your way in.)
If anyone is really interested in his work (and if you do UI-related work dare I say, you probably want to be), I'd recommend the book "Maeda @ Media", it's a great guide through his earlyish work and process.
The line has a sense of arrogance. Although it is true, it might not need the mention.
People sometimes look at his work and think it's very simplistic and/or retro. Part of the art is the process it took to get there.
Maeda is an artist before he is an engineer so what he creates is more experiments using code.