The performance is very fast for processing and searching logs. This is the biggest advantage Scalyr has over the competition.

Scalyr agent is pretty feature-rich, performs well, and is open source. Also, really enjoy the log4j/logback appenders to facilitate getting logs to Scalyr. I also like the parsing functionality. Can do some really robust things. Oh, the support from Scalyr and openness to listen to suggestions is unmatched by any other service we tried. Also, the alerts are vert interesting.

Scalyr is lightning fast. Makes searching logs a joy.