Which gets less blur handheld at 70mm?

a.  My 24-70 at f2.8 OR

b.  My 70-300 at most open (f4.5) and VR2?

I'm in a situation where light is marginal and I'd rather not use flash.

In other words, does the VRII on the 70-300 compensate for the wider aperture on the 24-70?

--
Sean