Sigma 85mm F1.4 or Canon 100mm F2.8L ???

My gear : 5DMarkII, 17-40L

I love my current 17-40L for shooting landscape photography, i plan to get myself a portrait Lens for Portraits as well as Wedding shoots. i wonder which lens is most suitable for me :

Sigma 85mm F1.4 or Canon 100mm F2.8L ???

i choose sigma since i cannot afford Canon 85L but i heard that Sigma 85mm got a lot of bad focusing issues,

Please advice, Thanks