drtweak :
I got the Seagate Momentus XT 750 Gig SSHD thats is 7200 RPM vs my old 250GB 7200 RPM. Honestly. didn't see much of a difference. If anything If you laptop has 2 Hard drive spots or a mSATA spot i would go with a SSD and a seperate HDD. Otherwise just get a nice 7200 hard drive.
ive actually had the opposite experience. My seagate momentus xt boots up noticeably faster than my Western Digital Black 7200 rpm and a little slower than my samsung 840 pro.
not sure about other hybrids, but i would recommend getting the momentus xt over a regular harddrive.