Speaking of the 58 1.4G, the problem I have with it is the price. The 1.8G is $220 new while the 1.4 is $1600. Sure the 1.4 is a little faster, and has a bit more glass. But the build quality is essentially the same - plastic. And the QC is the same with many people having to return lenses until they get one that focuses properly.
Nikon supposedly said that the 58 1.4 has a huge mark up just because they want it to appear to be a premium product. And premium products are expensive.