I'm a huge Beck fan, have been for almost 10 years now and I can thankfully say that Guero is a worthy addition to his discography. I've listened to the album 3-4 times now and my early impression is that the album is very good but probably my least favorite of his major label albums. My early favorite song is Girl, but that's because i'm a sucker for catchy pop songs with background vocals. Here is my order of best to worst (even though all his albums are great) Beck albums.
1. Mutations
2. Odelay
3. Sea Change
4. Midnite Vultures
5. Mellow Gold
?. Guero