W00t! Just had a really long Sigil LD with high lucidity! My first good LD in my whole life! Eat that, WILD!
To answer your Q holy reality, when it comes to Sigils vs Autosuggestion in matters besides Lucid Dreaming, I still think that the messages to your Subconscious are a bit stronger with Sigils because of the creation process. They both work fine, heck they even work good when used together, but I still have a gut feeling that Sigils are better.