While both sentences are probably grammatical, I’m wondering which one is preferable. To me, the first sentence sounds awkward, but the second sentence may have an unnecessary is. Basing your answers on grammar (or a style rule), which sentence should be used, or better yet, which sentence is preferable over the other? Is the second is in the second sentence necessary, and if it is, what does it do to improve the sentence?
PS: Based on parallel structure, I personally believe that the second sentence is more correct.