Well, SLC is the fastest and most durable, but most expensive. Some SSDs treat a portion of the NAND as an SLC write cache, which is generally a performance and longevity optimization.
MLC, which used to be mainstream, is slower than SLC slightly, and has far less durability.
TLC, which is the current mainstream, is slower still, and has horrible longevity / cell durability. However, it's cheap to make, and with a firmware tweak to enable an SLC cache area, they can perform acceptably for most desktop users.
The new kid on the block, 3D NAND, in TLC form currently from Micron, is in the Crucial MX300 and Intel 600p M.2 SSDs, and the Adata SU800 Ultimate. Supposed to have better characteristics than just regular planar TLC. Lower power, faster, better longevity, possibility comparable to MLC.
Samsung also has been producing 3D V-NAND, which is a vertically-oriented 3D NAND cell. This is used in the 850 EVO, in TLC form, and the 850 Pro, in MLC form. Performs well, and has decent longevity, in Samsung's implementation, but you'll pay a premium for it.
There's talk about a QLC, quad-level cell, for write-once,. read-many applications, and archiving. I'm not aware of any products shipping with this yet though.
As of today, MLC is starting to dry out, and the only current MLC SSDs on the market, are Toshiba's VX550 drives that were just introduced.
The Mushkin Reactor is also MLC, as is possibly still the Kingston V300, and certain models of the Sandisk SSD Plus, although WD bought SanDisk, and is probably going to phase those out.