Spelling Mastery has a fair amount of overlap with AAS. Both use phonemic strategies as the first line, and whole-word memorization for irregulars, transitioning to morphemic (etymological/word-root) strategies in the upper levels. Both programs expect small, frequent sessions (15-20 minutes a day). Where AAS is intended for individual work, Spelling Mastery is a classroom or small group intervention, with a heavier worksheet component, with the handwriting and independence factors that come with that.

I would consider your situation and your child. Here are some sample lessons from Spelling Mastery:

http://nifdi.org/documents-library/.../162-spelling-mastery/226-sample-lessons

It doesn't look like it would be easy to purchase as an individual, other than through old editions on Amazon, etc. If in a school setting, though, I think it would be good.

...pronounced like the long vowel and first letter of the alphabet...