I purchased the bundle set for my son and have currently gotten through the first two books, Making Lemonade and Fear Not. Overall I have found the lessons to be well-written and beautiful, with nice pictures and relatable examples provided. My son was most excited that the bible study came with a sticker sheet so he can put stickers wherever he wants, and I thought the twistable crayons that come with the bundle lesson were a fun touch.
I do regret purchasing the Primary Level for him and wish I had instead purchased the Pre-K level, however, just based on his readiness. While he will be turning five very soon, I felt some of the engage questions in the lesson aren't really relatable to him yet as he is so young and he doesn't care much for drawing. If you are hedging back and forth between doing Pre-K or Primary like I was, I would recommend you just go with the Pre-K as it comes with a lot of stickers and all kids love stickers. If I could go back in time, I would have gone with the younger lesson for my son.
One tiny critique I have with the lesson for Primary is that it is designed for the grown-ups or older siblings to read to the younger kids, but the script we are supposed to read has a lot of "I" statements (such as, "One time when I was younger, I experienced..."). As we are reading this to the younger child, it sounds like we are talking about our own experiences instead of the author's experiences. I wish that those stories were written differently to avoid telling someone else's story as personal experience.