I'm actually currently revisiting these two albums; I've been listening to full blast all day, non-stop. I think I threw Colour Of Spring in there too just to keep it fresh - great album as well.
These two albums, the dynamic duo, man, I don't even know where to start with them. They don't sound a tad dated, and though, I wasn't even around when they were originally printed, I can tell you compared to most albums of the day, they sound so crisp and vibrant - it's great, especially Laughing Stock. As for my preference between the two, I'd say Laughing Stock takes it for sure. Spirit Of Eden had this mystique and watery atmosphere that I loved, but I admire the more extended and experimental arrangements of the latter. Atmospheric Music, it's all about that atmosphere.