I first learned Ancient Greek with JACT. The textbook that's going to work best I think depends a lot on your own skill level with language and grammar and your learning environment (classroom, independent, etc..). JACT's fine but for me, it's not my favorite. I have not opened the textbook in about 12 years but I recall that it introduced concepts gradually and not at all in a traditional way. This could be seen as a positive or negative. White and Sidgwick are my favorites because they all stress a good amount of composition from the very start.
I agree too that the JACT readers are nice. Those were fun.