My rear ESA shock recently failed on my 09 GSA, but I was still in the warranty window. However, I'm firmly in the Wilburs ESA replacement camp. If the front fails after April (warranty end) then both are getting Wilburs. If before April, then the factory one. Part of my reasoning is price, BTW. I also like the ESA functionality. That's my 2 cents worth.
2009 BMW R1200GS Adventure