It's pretty simple why Voxengo plugins are so good - Alexsey has a better ear compared to other developers.
His plugins sound so 'musical'. I've used many other plugins that technically perform their designed function, yet somehow just don't sound good.
I now have a whole set of expensive plugins that are just taking up drive space. They simply don't sound as good as thier Voxengo counterparts.
Start with GlissEQ on the lead vocal bus. Use a lil bit of MSED on the backing vocals. Add a juicy amount of VariSaturator while mastering, topped by an Elephant. Even when he can handle hot temperatures, I like him cooking slow. Stir together & taste with SPAN. Serve & Enjoy :)