What is MSATA. What are the benifits for using MSATA MSATA is the technology used for the majority of today's hard drives and people generally like it. But SATA wasn't designed for tiny portables. That's why the guys behind SATA are introducing mini-SATA, or mSATA for short. It's supporting 1.5 Gb/s and 3.0 Gb/s transfer rates (peaking at half the speed of existing SATA), mSATA is intended for drives that are roughly the size of a business card.
Some motherboards out there carries MSATA slot. I believe most user would put MSATA SSD on it.
PRO:
Comes in handy.
Use SSD as drive cache if motherboard supports.
Save an internal drive bay.
CON:
Small capacity since the MSATA card itself is small. It only could has 3 memory chips on it.
Low speed, max speed is 3Gb/s

Motherboards that carry MSATA port:
GIGABYTE GA-Z77-D3H
GIGABYTE GA-Z77X-UD3H
GIGABYTE GA-Z77X-UD5H
GIGABYTE GA-Z77X-UD5H-WB
GIGABYTE GA-Z68AP-D3
GIGABYTE GA-Z68XP-UD3