The best replacement for syslog-ng is rsyslog.

The best alternatives to syslog-ng are rated as following:
★★★★★  rsyslog
★★  logstash
★★  metalog
★★  syslog
★★  nxlog
  sysklogd

Your alternative for syslog-ng is not listed? Suggest!
Speaking about syslog-ng, one probably shouldn't forget about loganalyzer.

Other search terms related to syslog-ng and their ratings are:
★★★★★ loganalyzer
★★★★ splunk
★★★ logrotate
★ rsyslog
You have in mind a companion for syslog-ng and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of syslog-ng in all years. Click on graph for more.
syslog-ng
rsyslog
logstash