From what I can gather, Samsung is the way to go for SSD encryption. The 470 (PM810) received FIPS 140-2 certification, and the algorithms used are in that report (AES-256 and SHA-256). It also does a Firmware check, to ensure it hasn't been tampered with. Unfortunately, the 830 drives don't offer encryption in the retail market. The 830 has encryption in certain OEM drives like the new 830 mSATA drives.
From the little that Intel is willing to offer about their 320 drives, the fact that they claim the password hash is saved in the drive (never save passwords in any form when dealing with encryption), and that the hash algorithm is unknown leaves a lot of people unsettled about the security really offered by the drive.
Sandforce drives have reportedly run into a HUGE security issue where updating the firmware essentially wipes the passwords, but makes the information on the drive available to anyone with physical access to the computer. This essentially proved that the passwords played no role in encrypting the drive and they are completely open to compromise.
I've done a little searching, and the reliablity and security offered via ATA passwords (used in the decryption process) is very concerning. First, many BIOS don't offer it. Second, most of the ones that do, only offer up to an 8 character password (not very secure). Some BIOS implementations alter the password before sending it to the HDD/SSD, meaning that if you remove the drive from that computer and put it into another computer it won't work, even if you enter the same password. This means that if your motherboard or laptop breaks you lose all of your data, and in the case of Intel's 320, your SSD becomes a brick("unservicable," as Intel would put it). There appears to be no standardization for ATA password implementation in the BIOS. Since many consumer grade SSD/HDD self-encrypting-drives (SED) rely so heavily on it, you would think there would be a better standard. Check your BIOS manual before even purchasing a SED.
Encryption on SSDs seems to be primarily for the purpose of secure erasing the drive in a timely and reliable fashion and less about providing an active security measure to the customer.
Based on a days worth of research on the internet (we know how reliable that is), the only SSD I would feel at all comfortable using to protect information would be the Samsung 470. That is my 2 cents.