Memory for MBP 13" & 15" 2010

I'd take the 1333Hz [your first link] since its the stock version of your computer, the 1066Hz is lower then what you have now...or is it the bandwidth...

anyways buffered is most stable but one clockspeed slower, it is typically used in servers and high end hardware, it is also more expensive.

unbuffered is cheaper and used on regular computers.

Will it make a difference to you? probably not. Unless your running some trippy applications.