I've got a really good friend who was debating smaller SSD or Hybrid, and finally bit the bullet on a 750GB 7200rpm / 8GB hybrid from seagate (I think).
He loves it, and it is a dramatic improvement from the hard drive alone. Applications are much less painful to work with, and same goes for startup and shutdown. No, it's not as fast as the SSD in my air, but it's so much better than the original drive, it's like a new computer.
Of note, he added it to the 15" 2.66Ghz i7 from mid-2010, 8gb ram... and it previously had the 500gb 7200rpm drive.