We just had to make this call and went with the hybrid. Go lay on some mattresses, even if they're not the ones that you're looking at first -- we had no idea how smushy the memory-foam only ones actually were; it was like sleeping IN the mattress rather than on it. The Hybrid was the right amount of swish for us. (And if that changes, we can add squish with mattress toppers, but you can't really remove squish, so err on the side of less.)