It's comedy. It's really quite funny, and even funnier if you are in emergency services. It's not a top ten of all time comedy but it's plenty funny compared to a lot of today's garbage.
Comparing it to Brooklyn 911? What about St Elsewhere, ER, Grey's Anatomy, etc... all based on the same premise. What about every ridiculous fire, EMS, police and ER drama? Are any of them based on any reality other than soap opera? If you want ridiculous premise disguised as drama, then watch Chicago Fire, etc.... ad nauseam. If you need a half hour of light comedy, watch this instead.