Yes; hard to divine which is better purely on the basis of the reports, I agree. However, Eirias always had a reputation for helping the brighter children better. Conversely, they didn't support those who struggled as well as they might.
Reading the reports closely, Eirias has the edge in Improving quality: Good (YJB is Adequate), Partnership working - Excellent and in both English and Maths Eirias has the edge. Sadly, Estyn changes the ways in which it presents data, making detailed comparisons difficult, but their GCSE and A Level examination performance has always been one of the best around.