U.S. naturalization: 5 years vs. 3 years married, which faster/smoother?

Question

I am about to apply for U.S. naturalization and qualify for two of the eligibility criteria, namely, both :

"I am at least 18 years of age and have been a lawful permanent resident of the United States for at least 5 years."

and

"I am at least 18 years of age and have been a lawful permanent resident of the United States for at least 3 years. In addition, I have been married to and living with a U.S. citizen spouse for the last 3 years, and my spouse has been a U.S. citizen for the last 3 years at the time I filed my Form N-400."

Are there any indications that filling under either of these eligibility criteria is easier, smoother, or faster?

My guess is 5-year eligibility would save the submission and verification time of marriage documents and could be better. Unless for some reason applications based on marriage process faster on average?

Can anyone --- maybe experienced immigration lawyers ? --- provide any evidence one way or another?

Answer 1

Are there any indications that filling under either of these eligibility criteria is easier, smoother, or faster?

Assuming one satisfied the continuous residence requirement as well as the physical residence requirement, N-400s based on 5 years of lawful permanent residency are easier than N-400s based on marriage processed, because one doesn't have to prove the genuineness of the marriage.

The USCIS doesn't release statistics on which one is faster to process. However, this spreadsheet contains >200 application timelines for Seattle that you can use to see whether marriage-based N-400 applications are faster.