I'm so tired of that comparison.
Heres the difference: Rails is programmed on Ruby.
Rails in itself is, to me, not that impressive. It does a lot of things right, but it does probably just as many wrong. Not the least of which is scaling.
But the advantage that Rails has is that its programmed on top of Ruby. And for that reason it will never be truly akin to the monstrosity that was VB.
Except in that it attracts poor developers. But, thats simply because its easy. The trick is finding the people who use Rails because of Ruby... not the other way around.