I have written my views on John's albums on my Quiet City website, which you may (or may not!) find helpful.
John's work from '97 onwards has been mostly electronic, and minimalistic in approach, using a lot of old analogue sounds. You'll hear a lot of Kraftwerk influence in the music. One way of describing an album such as Shifting City or The Pleasures of Electricity, is a continuation in sound and style from Metamatic.
If you're after a good melody, then I'm sure that From trash, The Pleasures of Electricity, Crash and Burn or Sideways will not disappoint, whichever you choose!