We’ve used or are using Core P4/5, Core B, and Core C. My kids are now 5 and 8.
The Usborne history books are what engaged my ds8. He liked the pictures and will read them on his own. I’m not crazy about CHOW, but lots of people here and who use SL like it. Some people incorporate the SOTW books alongside these first 4 cores (B,C,D,E). I just started using SOTW2 alongside Core C. I use it as the spine bc we’re finished w/the Usborne Time Traveler book. I don’t think getting through the history portion is difficult. There is also usually a missionary component to the history – for this core its Window on the World.
The other parts of the core are literature and bible (and now the LA is included also). The literature read-alouds are good. I personally have a hard time reading aloud for a long time, so I’ve been getting them on audio whenever possible. I would say that these books are scheduled to move pretty fast.
The Bible portion is ok. I like the scripture memory verses. We use the SCM model (the box) and just plug in the verses. But I’ve gone back to using the VOS bible for now.
Most people, I think, choose SL mainly for the IG (the schedule). They know they want lots of great books, but scheduling them out is what bogs them down. Included in the IG are vocab words and definitions and reading comprehension questions. Some people use all this stuff, and some, like me, don’t use any of it. 🙂 We do narrations (oral and drawn) and I think that’s sufficient.
We tried using “older” books, but ds just wasn’t into it, and really, neither was I. The Usborne books aren’t perfect, but they do cover history well enough (for a spine) and the illustrations caught my son’s attention. In the lower cores (B & C) you use the Book of World History and Time Traveler. My son especially liked TT.
In the American History cores (D & E) you don’t use any Usborne books. They use something else entirely for the spines. I also keep hearing that the literature is beefed up quite a bit – meaning there is more to read and the books are more challenging than in B & C. Its possible that one may feel they move too fast through them. But I would also say its easy to skip a read-aloud if you want or need to.
I hope this helps somehow. 🙂 Becky