They are so mealy. The flavor is nice, but I hate the texture. Empire apples have a similar tart flavor, but with a crisp flesh similar to a golden or red delicious.
If it was mealy, it was probably improperly stored or grown in too warm weather. They aren't normally mealy. They're more tender and less crisp than Honeycrisp and have a pleasant texture.
You're likely not getting good McIntosh apples in your area. The texture should be similar to a typical apple, but not as crisp as Honeycrisp. A slice of McIntosh should snap if you try to bend it.