We tried RS level G and it was misery. It went so quickly for one thing. We switched to Teaching Textbooks and it has been much better. Their website has a test to take to determine which level is best, and our daughter started with level 7. They explain things generally very well. The only drawback we’ve had is that my daughter tries to do all the problems in her head and often gets frustrated, as the questions are on the computer. There is a paper workbook too, but not as much fun as the noises (which you can turn some off) and pictures on the computer.
Hope this helps.