We've been very happy with the instruction our daughter has been receiving. She is in the tiny tots class 2 days a week, 3 when we can make it. What I've really loved is the appropriate level of discipline and self control they are asserting on the kids. I love the 'yes sir, no sir', and they know my kid well enough now to know when she's faking a potty break and when it's really an issue. They never let the kiddos accept anything other than their best shot. They do especially well with new kids and usually assign one teacher to a new kid -- there can be a lot of tears as for some little guys, this is their first activity out of the safety of their home.
It does seem pricey to me at $130/month (the pricing can be lower if you lock into a time commitment -- we go month to month) but you can attend as many classes as you would like at this price. So you can really make it worth your money. And if karate is something your child wants to commit to, it's a total bargain.