I’m a little late in entering the discussion, but I am currently working through RS Level B, 2nd Edition with my two oldest. I also own RS Level A and B, 1st Ed as well, so I can share from experience. We were in the middle of RS Level B, 1st Edition when I attended a Homeschool Convention and got firsthand knowledge of the difference between the two editions.
I actually switched my girls over to the from 1st Ed to 2nd Ed of Level B because if we hadn’t, they wouldn’t be prepared to enter the 2nd Edition of Level C! I loved the 1st Ed, but the 2nd Ed. is even better! It was worth stepping back so we could go through 2nd Ed. Level B. The 2nd Ed includes more games, more concepts, more assessments, more explanations, more formal review, and the page layout is much more pleasing to the eye.
Bottom Line: the 2nd Edition is stronger, not weaker than the 1st Ed. Truly, it is not dumbed down in the least. RS has always been accelerated, and the 2nd Edition takes it further in this direction, not away from it.
2nd Edition was not created to allign itself with Common Core! It simply has Common Core mentioned so that it could be used in classrooms where Common Core is currently being enforced. (God help us to remove Common Core from America.) The only thing that you’ll find is a code/reference for which Common Core standard that lesson particular lesson meets.
Does RS 2nd Ed. meet Common Core standards? Yes.
Does RS 2nd Ed. exceed Common Core standards? YES! YES! YES!
I started by two oldest on RS and Singapore from the beginning, but after two years of using both curriculums I’ve seen that RS has been easier for me to teach and very effective for my girls. They learned from RS and applied that knowledge to their Singapore workbooks. Boy, those RS games really work!
All that said, we’re behind on math now since i switched them over to RS B, 2nd edition in the spring of 1st grade. I had hoped to continue math through the summer, but alas, my mom had cancer and so we didn’t school through the summer. So, we’ll march on through the end of RS B, and head into C (2nd Ed.) this fall. I’m dropping Singapore so it shouldn’t be hard to catch up. Two maths was too much, especially now that I’ll be starting my youngest in RS A (1st Ed). Note: It is okay to start in RS A ist Ed. and then switch to RS B 2nd Ed, but once you complete Level B (1st or 2nd) you’re pretty much locked in to whatever Ed. you chose for your Level B. There are just more concepts introduced in the 2nd Edition Level B, and this lays the foundation you need for 2nd Ed. Level C. Hope that makes sense. Call RS if you have any questions or ask questions at their booth at the next homeschool convention like I did. It was worth it!