metrictools contains commands for capturing measurements and for visualizing the data. However, there are no commands specifically inteded for monitoring or alerting.
The recommendation for monitoring/alerting is to use an external system that reads the metric data and calculates the alarm states. You could do this with a custom script or a third-party alerting system like nagios.
All metrictools components are simple stateless services. So it all depends on the backend database. If you're backend database is scalable and highly available then so is metrictools.
metrictools needs a reasonably modern C++ compiler and standard library. In most cases where the code doesn't build it's due to some problem with the local build environment. We always appreciate bug reports so we improve our build system, but often the best workaround for the moment is to download a binary release from the downloads page.