Well, it was a very long time ago when I read them. Scalzi himself seems to admire the Retief books.

Something I forgot to mention about The Android's Dream is that it's very much a Washington novel, which people familiar with the area ought to find amusing. He bobbles the distinction between Arlington and Alexandria at one point, but for the most part the DC-area geography is entertainingly futurified (Metro has been refitted with maglev trains).