The Court rejected Aquino's by a 9-5 vote. They found that the constitution only requires 250,000 people for cities, not provinces. In fact, Chapter VI, § 5(3) of the Constitution states:
Each legislative district shall comprise, as far as practicable, contiguous, compact, and adjacent territory. Each city with a population of at least two hundred fifty thousand, or each province, shall have at least one representative.
At the very least, the drafting is poor and ambiguous. However, it seems that "province" is separated from the 250,000 population requirement. Other politicians have pointed out that the provinces of Batanes, Camiguiin, Siquijor, among others, have less than 250,000 inhabitants, and yet have their own congressional districts.
The significance of this case probably isn't in the jurisprudence or doctrine - the outcome seems like a reasonable enough interpretation. However, the decision could impact Aquino's political standing - either striking a blow to his candidacy, or increasing his reputation as the anti-Arroyo (my guess is the latter is more likely).