I have worked in public safety for many years and my husband is a firefighter. This is the best childrens' show I've seen about firefighters, fire safety, etc. The safety lessons are VERY consistent and solid. It's refreshing when other shows about similar topics are often very hypocritical... touting safety messages while portraying, in a positive light, the "rescuers" engaging in excessively dangerous behaviors themselves.
Another reviewer here was critical that one of the characters acts irresponsibly sometimes, but I think he/she's missing the point, as this character doesn't ALWAYS act this way, and when he does do things that are unsafe, he is clearly portrayed in the show as foolish, there are clear negative consequences for his actions, and the other characters who act more responsibly are portrayed very positively.
I greatly appreciate that this show portrays characters like a female firefighter and an interracial couple in a very normal, straightforward light. They are portrayed just as every other character on the show is.
In my experience and opinion while this show is appropriate for the 2-to-3-year-old set, most kids won't be very interested until they're a bit older than that. The differences in accent, culture, and language seem to be intriguing to some kids, but too confusing to others, as far as interest goes.