Disclaimer: I was a reviewer of POODR, and my name is in the 'thanks' section.
SBPP is a classic for years, and POODR is new, so it's hard to make a comparison. SBPP takes a little bit more effort to apply to Ruby, as Ruby's features are a bit different than Smalltalk's. POODR is excellent, but the one thing that I don't like about it is that it uses the physical metaphor for objects: bikes and wheels and mountain bikes. Getting out of the mindset that objects were only for physical analogues was one of the hardest things for me to level up with in OO design, so that part was slightly disappointing. But everything else about POODR is great, and I'd recommend it to anyone who programs in dynamically typed languages.
SBPP is a classic for years, and POODR is new, so it's hard to make a comparison. SBPP takes a little bit more effort to apply to Ruby, as Ruby's features are a bit different than Smalltalk's. POODR is excellent, but the one thing that I don't like about it is that it uses the physical metaphor for objects: bikes and wheels and mountain bikes. Getting out of the mindset that objects were only for physical analogues was one of the hardest things for me to level up with in OO design, so that part was slightly disappointing. But everything else about POODR is great, and I'd recommend it to anyone who programs in dynamically typed languages.
Really, you should own and read them both.