My most recent experience is with Liberty has a lot of good child-sized equipment as well as good teachers. My 5 1/2-yr old has had, oh, about 10 lessons at Liberty (beginning when she was 4 1/2 last year) and just loves them. Quite a few times, group lessons turned into private lessons because no other students signed up. And the instructors often went way over their allotted time, obviously geniunely enjoying themselves and even later briefing me on what they had taught and what we should practice.
Of course, if you've got the money, the best is go out West where the conditions are better.