I like it better than the WJ. My go-to is the WIAT-III, but with the new KTEA coming out, I am leaning that way as a preferred achievement test. I would put the KTEA and WIAT about on a par. I know some people prefer the high ceiling of the WJ for gifted kids (and ceiling effects can be an issue on the WIAT), but I like the depth and complexity of the tasks better on the KTEA and WIAT. I think they are better representations of the academic skills they purport to measure than the WJ's short-response tasks. Especially in written language.
On the KTEA, the math concepts subtest can go up to calculus, while the calculation subtest covers through a variety of algebraic computations.
It sounds like you have an experienced evaluator, which will be very helpful.
