Best blues guitarist, Clapton or Green

Neither: if we didn't have both of them to enjoy this question would be moot, and it is.

As stated earlier- SRV is the best IMHO- fluid, emotion, technique and never boring.
However, Clapton has some real gems out there, especially in his drug and booze, broken hearted rage for Layla. Nobody knows you..., Have You Ever Loved a woman, Bell Bottom blues.
One of the best all time recorded guitar works, IMHO is Crossroads. Attack and emotion and fluid. Burns it up!!! And Spoonful??? Another one.
Of course, Clapton did Beyond The Cradle- this definitely put him in the realm of greats.

I never understood the appeal of that generation of technically refined rather timid British guitar players. Give me the raw intensity of Freddie King, Hubert Sumlin (Howlin' Wolf's guitarist), or T-Bone Walker anyday.

JOHNNY WINTER

neither.......Muddy Waters, you did say blues guitarist. I think Clapton is more rock. If you really want the blues, give Muddy a try.