I don't know if Rubio has a more valid claim, it's just very different....born in the USA, US citizenship at birth, but legal residents though not citizen parents.
Rubio's case is more of if a person is natural born to one country, which one is it?
The sad thing is, eight years after the Obama situation, eligibility STILL hasn't been defined.
At this rate, we're not that many elections away from a person being President of the US and some other country at the same time.
JMHO
Marco Rubio is a U.S. citizen by naturalization at birth under the authority of the same U.S. Immigration and Naturalization Act of 1952 as Ted Cruz, only in an earlier paragraph of that statutory law regarding the birth of a child within the jurisdiction of the United States with foreign parent/s.