I did Montessori between ages 6 and 15, then transitioned into more traditional education for the last three years.
The main difference was how much more challenging Montessori education was. The teachers really observed me and how I performed on assignments, and they could tell when I needed more of a challenge, and assign something to me that was just at the edge of what I was able to do. In the traditional education, if I consistently just did the bare minimum expected of everyone, I was a double-plus A plus student.
I was also allowed to explore subjects that interested me in greater depth, as long as it didn't come at the expense of subjects I found less interesting. I learned a lot of English and maths in the first few years!
If I had a disagreement with a Montessori teacher, we would sit down together and have a mature conversation about it and reach some sort of mutually beneficial solution (yes, even when I was under the age of 10!) In the more traditional education, there was the assumption that if I disagreed with the teacher, I was wrong and should shut up. (I ended up not passing a few classes in the traditional school because of disagreements with the teacher – I simply stopped attending the class at that point. Didn't seem productive to go on.)
I also had a lot more spare time in the Montessori school. As long as I did well on the work assigned to me and didn't bother my classmates, the teachers didn't really care how I spent my time. I could sit in a corner and read or do long multiplication, or go out and kick around a soccer ball. I would like to think this helped me learn independence.
On the other hand, I also have a notable lack of respect for authority figures. I like to think this is good, but it has also gotten me into trouble for disagreeing with hardline managers, refusing to do things I think are unethical, etc. I think some of this can be attributed to the Montessori school, where respect was based on fact, rational argument, and patient listening, rather than who should be commanding whom.