Because core curriculum is a huge investment, it is important schools are savvy consumers. Multiple research-oriented organizations completed much of the leg work to help you analyze which core best fits your district needs.
When looking at different curricula, be mindful of and seek out the components of structured literacy: evidence-based, highly explicit and systematic teaching of all important components of literacy.
Carol Dissen- Using Instructional Routines to Enhance Core Reading & Explicit Instructional Design and Delivery Principles
Explicit Instruction for All Students