For my projects I almost always use NewRelic (free works fine, unless something gets really wrong and more info is needed). Additionally, I use my own open-source application and write custom setups to collect data of whatever I want ( https://github.com/andriussev/server-seer ); from there on the data can be processed internally or, I tend to use my wrapper for it on https://sysplatter.com.

Obviously, that would not work with log data.