The songs are good, the arrangements are properly gloomy and, well, "shadowy" - lots of nice slide guitar and stuff - but still light and airy as you'd expect for the material. I'll say this, the stripped down approach makes the songs sound different than the way others typically have done them. Only the vocal melodies betray that these are old pop standards instead of old folk or country songs.
This is just a first impression. The main problem with Shadows is that it does get pretty samey, though it's all fine and pleasant. The short length of only 35 minutes helps, though. It's a nice, relaxing album. I'd probably give it a 9 on John's scale, but keep in mind that I'd also give almost every Dylan album at least one more point than John did.