We use Growing with Grammar, and my ds like it a lot. He picks that subject first every day, since he knows it will be easy for him.
We are actually a grade level behind in Grammar, but that's OK with me. We started Level 1 when ds was in 2nd grade. The Level 1 didn't seem to match up with our first grade work. In first grade, we are still just putting phonics together and learning to read. There would have been too much reading and writing in Level 1 for our first grade work.
I looked at their online store today, and they carry eight levels of Growing with Grammar.