What is the difference between the simms gortex bootfoot waders and the
simms g3 guide stockingfoot waders?

Right now I have red ball non breathable bootfoots. I want to get the
most comfortable warm waders possible. What is the reason for the g3's
not being bootfoots? I have never worn stockingfoots, what is the
difference between stockingfoot and bootfoot practically speaking and
comfortwise?

What are other waders that are gortex and comparable in quality?