I have taught with Harcourt. It is pretty sequential and straightforward in state curriculum. It used to have an 'enrichment' addition that the teacher may or may not have.
Pros/Cons I have heard about Singapore is that is straightforward and logical. It encourages 'drawing' and manipulatives to problem solve. Pros is that is stresses mental math a lot and has lots of mind games/benders. If you have a kiddo that learns this way, fabulous! Cons were that it has timed elements that some students can struggle with and also if you 'miss' a portion, it can be hard to fill in. Fewer concepts are covered in a time frame, but they are mastered vs. revisited. So if you miss a concept- you may have to go back and master it before moving on.
