Look underneath the simple browser- or mobile app-based user interface of most enterprise software applications today and you will find a veritable spaghetti bowl of code, pulled together and orchestrated from multiple different sources, locations, owners and indeed underlying languages. The construction and operation of application software today is far more complex than ever. At the same time, user expectations of uptime, latency and responsiveness are way higher than ever before. Taken together this means that the user acceptability level for application downtime is very low; but the potential likelihood of application downtime is very high. To resolve this big enterprise IT problem, you need cloud monitoring software. There are three vendors in the news right now; DataDog ($DDOG), Dynatrace ($DT), and NewRelic ($NEWR). Which of these stocks should you buy? Depends who you are. We explain below.