What is the difference between mSATA and SATA SSDs?

According to Wikipedia:

Mini-SATA, which is distinct from the micro connector, was announced by the Serial ATA International Organization on September 21, 2009. Applications include netbooks and other devices that require a smaller solid-state drive. The connector is similar in appearance to a PCI Express Mini Card interface, and is electrically compatible, however the data signals (TX±/RX± S-ATA, PETn0 PETp0 PERn0 PERp0 PCI-express) need to go to the S-ATA host controller instead of the PCI-express host controller.

Due to the fact there was no standard in the beginning there is still some fogginess around this subject. What makes this clear is this application note from NXP explaining how to use a PCI-express/S-ATA router chip. Of course one does not have to use such a chip, 4 simple three way switches would suffice.

Also, you can find another reference here.

Looks like mSATA is like mobile sata ssd plugs into a mini-PCIexpress slot on a notebook. sata ssd's can work as a replacement hard drive in the normal slot of a notebook and in desktop computers. Found this on the Msata on the notebook review.

There's no difference. mSATA is a regular SATA interface over a mini-PCIe connector.

http://en.wikipedia.org/wiki/MSATA#mSATA

There is no electrical difference between the two, it's 1:1 connection. that's coming from the forum at Crucial, a maker of MSATA itself.

You can find the answer in Crucial Forum - Secure erase Crucial M4 (msata) with adapter?