Great vid on the topic DEFCON 16: Solid State Drives Destroy Forensic & Data Recovery Jobs: Animated! - YouTube
Old thread I know but I've just determined that (at least on Linux) a LUKS encrypted drive is preferable to a hardware encrypted drive. Hardware encryption is available on my Samsung 840 EVO SSD but I don't trust it - hardware encryption can be backdoored. My LUKS encrypted drive(s) keys are AES set by me and only me. This takes nothing away from the original post about how SSDs are probably more secure with erasure than spinners.
Very True Melbo.... ALWAYS use the Open Source Encryption, where folks have read, and understood the Code, and deemed it BackDoor Free. This is why we use Phil Zimmerman's work, (PGP, GPG, etc) for MonkeyNet. It is well researched and KNOW BackDoor FREE. In today's world, who do you trust? Yourself, with self-Generated Encryption KeySets, or some Packaged Encryption System from Known Compromised outfits, like MicroSquash, Apple, Google, the Phone/Cellular Companies? That is the REAL Question.... .... YMMV.....
I use a program called ccleaner, it's free, and aside from the obvious cleanup utilities under "tools" there is a drive wiper tool where you can select the number of times it will be over written. I believe you can pick 3, 5, or 7 times. It takes a while, but it'll clear them out. Not sure why, but an older revision labeled them dod, nsa, or something like that. That older version also had a 35 time over write option. Never tried it, but was tempted just to see how long it would take.