I had the genuine BMW ones on my 08 GS1200 (about £250 in 08). easy to fit and more importantly the cylinder heads can still be removed for servicing. Some bars do not allow this and if you use a dealer for servicing then your costs go up.
I have a set of the Hepco ones on a 2009 standard GS, around £135 with some searching, easy to fit, look very solid (thankfully untested so far) and I dont think they interfere with accsess to the cylinder head either.
i have a set of hepcos on my 08gs and they did what they were supposed to do when i had a low speed off a few months ago can't comment on any other ones
I fitted SW Motech ones and they were easy to fit, seem well made and the silver colour matches the frame nicely. Can't comment on their crash performance (touch wood)