We just got these and we've started them as our daily phonics lesson in conjunction with Hooked on Phonics. I'm not leaning towards dropping Hooked on Phonics, at least for a while.
Sweet Pea seems to like them and I like the rate of introduction for new sounds.
We're on Lesson 6 and I think by Lesson 16 or so we'll start hitting new material. I'm a little irked that after completing all of Hooked on Phonics Kindergarten and almost half of Hooked on Phonics 1st grade that it's only introduced 16 lessons worth of McGuffey's, but you live and learn.
I also really like the included slate exercises and that they are in cursive, so it’s a nice complement to the Cursive First work we’ve been doing.
Who says that newer is better?