Of those, I've used the Melvin, and a Rennen copy.
The dual pulley type (Melvin, Shimano Alfine, etc), those are best used for full suspension single speed mtbs (to account for chain growth during the travel of the rear suspension), or 2-by-1's or similar multiple chainring setups. They can certainly be used for normal SS's, and they'll work great, but they usually have a little more chainslap, which can be a little annoying.
The fixed type (Rennen, DMR STS, etc) are my favorite type, since you can set them to push-up mode (to increase chainwrap around the cog) and lock them in place to whichever chain tension you prefer. They can make it a little tougher to remove the rear wheel, but some have workarounds like the Soulcraft Convert's quick release lever. Even without a workaround, these are still my favorite types.
There are also the Surly Singleator types, which are single pulley sprung tensioners. Mixed results with these. I could never get my Singleator spring tight enough in push-up mode to avoid skipping. There are lots of people that can get these to work just fine though.
There are other types of non-standard chain tensioners that work really well too, like the Yess ETR-B. The ETR-B is my favorite, but it really only works with mtb's that use external cup cranksets. The max chainring size is around 40t I think.