I remember Wired putting out a pretty thorough article on it a while back.<EDIT>That article was actually on RISUG, which while still a polymer deposit claimed to maim sperm rather than blocking it.</EDIT>
When this hits the market I will seriously be considering it. Unprotected sex in a monogamous relationship is wonderful and it would be nice to take hormonal solutions out of the equation to make that possible with reduced risk of pregnancy.
Per the FAQ:
We want to get Vasalgel on the market as soon as possible, but all the proper efficacy and safety testing needs to be completed. Vasalgel is currently undergoing animal testing, product qualification and safety testing. Human trials are expected to start in 2016 (small trial) and 2017 (larger trials). If everything goes well and with enough public support, we hope to get Vasalgel on the market as early as 2018.
<EDIT> It seems reversibility studies have not been started yet </EDIT>