I have friends who live in both Kensington and Rockville.
The family in Kensington wanted to move to Takoma Park but, due to a temporary peculiarity in the real estate market on their street, couldn't. My understanding is that normally, houses in Kensington are more expensive than similar houses in Takoma Park. They are happy with their neighborhood school, and with the neighborhood in general, but it's not crunchy like Takoma Park.
The family in Rockville lives in a very cookie-cutter neighborhood, but is reasonably happy with the neighborhood school. They find Rockville more convenient for their particular commuting situation, but otherwise would prefer to live in Takoma Park if they could afford it.
In the 12 years that I've lived in Takoma Park, my car has been broken into twice. The only thing taken either time was pocket change, and in both cases, they either jimmied the lock or I'd forgotten to lock the car. Both incidents were some years ago. There have been a couple of incidents in my neighborhood recently where folks were robbed by people who entered through unlocked back doors. People in this area who are particularly concerned about property crime have security systems. I find the police department here very responsive, and I do not hesitate to walk alone at night, even quite late.
As for the schools -- I don't have any kids in school myself, but I've never heard anyone on the playground or in my neighborhood express any serious complaints about the schools. (This year, Takoma Park Elementary is being bused in its entirety to another school so TPES can be expanded and renovated, so people have complaints about that.) I know people who have kids in TPES and in Rolling Terrace, which serves the north part of Takoma Park where I live, and offers a sought-after Spanish Immersion program.
You might want to take a look at the survey results for schools in the neighborhoods you are considering:http://sharedaccountability.mcpsprim...ults/index.php
I don't know which school testing results you were looking at, but if you go to the state site:http://mdk12.org/
You can look at the data in a variety of ways, including finding out how many students have limited english proficiency (9.7% for Piney Branch Elementary and 37.7% for Rolling Terrace) and how many get free or reduced-price meals (36.7% for Piney Branch Elementary and 60.9% for Rolling Terrace).
I think both Rockville and Kensington are decent places to live. They both have a sense of local character and identity. They both have their own local government, which I think helps a place feel more cohesive. Obviously, I prefer living in Takoma Park, and think that, based on what you've said about yourself, that you'd feel more at home here. On the other hand, there are other places in the county with less crime and "better" schools.
I think schools are the hardest thing to compare, especially between states. It's hard to say whether the schools here are better or worse than what you're used to, for example.