Personally, Biol is my absolute favourite. It's what I'm interested and it's what I'm good at.
Although, I'm painfully aware of the fact that all biologists constantly struggle with their inadequacy as they watch chemists do real science. To be honest though, physics feels the most "scientific" to me. That says more about the community of physicists rather than the discipline itself. The major advances in physics of the last century or so have owed to the rigorous pursuit of objective evidence, even in spite of what are fundamental "realities" for humans. This is an impressive approach that Chemistry and Biology seem unable to replicate.
And on psych: it only feels like a science because it desperately tries to be scientific. It's needlessly pedantic and seems to hate the idea of being a social science.