I am a HUGE fan of the VixSkin dual density toys. At first, I thought "what's the big deal?" And then I tried them. I have Mustang and Goodfella - they are phenomenal.
I think it depends on what your g-spot likes. If your g-spot prefers lots of strong pressure, go with something firmer. But if your g-spot is like mine, it prefers lots of good thrusting - and the VixSkin provides that beautifully.
They're just super comfortable toys, seriously I can thrust vigorously for soooo long and not have any issues. Whereas with some of my hard silicone dildos I get sore sooner.