Tokina 11-16: Big aperture make make the difference?

I currently shoot wedding using Sigma 10-20 4-5.6 with my XSi or Xs. I really like the effect for human subject at 10mm especially indoors which could be dramatic.

However, I start to wonder if f2.8 at 11mm (Tokina) can make the difference if I want to to have some subject isolation since the DOF for wide angle lens is quite deep. Or the difference is not really visible?