Well, they aren't actually types of hard drive, they are types of interfaces rated at two different speeds. However, the Hard Drive portion is still the same and slower than either interface can handle.
So I guess the short answer to your question is "No"
they are the same if ur mobo can only handle sata 1.5
which limits the speed to 150 mb, if u have sata2 (3.0) then the speed is 300. they use the same interface and as i said it only makes a difference if ur motherboard can handle sata2. I think the speed is to do with the frequency in the cable sent from the Mobo.
i dont know the difference but i do know the physcial limitation is the metal not the electron. Whatever interface its on, the hard drive can only spin so fast and data can only be read so fast so the bottleneck right now is the spinning platters. A disk that spins at 7200 will be faster than a disk at 5400 and a disk at 10,000 will be faster than a disk at 7200rpm.
As for interface, i dont even think the IDE channel has been maxed out yet let alone SATA 150. So in my opinion SATA 150 and SATA 300 ought to have the same performance. However, if you are buying new, get the newer interface, its the same price and i not 100% positive i am right.
Short answer, No. They use different interface speeds (150MB/s vs 300MB/s) but that's it. And since the throughput doesn't even saturate the bus of the ATA 100 spec yet (100MB/s) the only real difference between the two types is price.
I should note that my comment about not saturating the bus of the ATA 100 spec, does NOT mean I am encouraging everyone to get a PATA drive. SATA drives are faster becuase they have higher throughput (and in some cases slightly lower access times)