We've all been there. I ended up creating an elimination list to narrow the options down:
1. Learning style - my kid did best with hands on, so I had to look for programs that could support that or I could make support that.
2. Fits into our desired scope, or is interesting enough to intrigue us. My son knew what he wanted to learn, so that was easy.
3. Availability - Needed to not require strange purchases that we might not be able to find. Everything inclusive or a list upfront.
4. Sturdiness. Math programs with paper manipulatives? No way. They had to stand up to repeated use.
We were able to narrow it down after that to one or two for each subject, and then my son picked from there. The good part? If we ended up not liking it, we could choose again the next year (or even that year!) when we knew more about other curriculums. I like not being held to one thing.