Catfolk is pretty comparable to an Aasimar.
The Catfolk have a slight boost on their stat bonuses compared to Aasimar, granted.
Aasimars get darkvision, arguably better than low-light (I argue it is

).
Aasimar get a +2 racial skill bonus on Listen and Spot checks. That is equal to the racial skill bonuses of Catfolk.
Catfolk have a movement bonus and a +1 natural armor bonus.
Aasimars gets Daylight (ok, it ain't the best), and Resistance to 3 kinds of energy.
The Resistances are a key strength of the Aasimar.
The Catfolk are certainly not OP compared to the Aasimar, and Catfolk are certainly sub-par to drow (Spell Resistance being the key ability for drow).
Just my 2 cents.
To add to the original thread: I love the planetouched. We also have a home-brewed gnoll, bugbear, and lizardfolk at +1 LA with no racial HD (for quicker access at lower levels).
Cheers