I use icinga extensively. It has a better UI but still suffers from the same downfalls the presentation presents. With that said, the solution proposed seems to be incomplete and a step back from what icinga/nagios provide.
opennms is a bit of a culture shock if you're used to nagios. It works kind of inversely, in that it wants to auto-discover the servers and services to monitor itself. Frankly, it feels very much designed around snmp imo (which I'm not saying is a problem, but it's different to how we use nagios).
It's also the opposite of nagios in that rather than lots of smaller moving parts, it is one big mega (java) process that does everything. Again, not necessarily a problem (though I happen to think so :), but different.
I also found opennms to be VERY complicated. I suppose nagios is though, first time around.
For some reason though, I really want to use opennms and keep going back to try it out, but eventually give up.
OpenNMS is great to run in addition to a traditional monitoring system.
Your traditional monitoring systems have hand-selected features to monitor and alert for. OpenNMS will just go out and discover everything you have (and graph everything without any intervention too).
You probably aren't monitoring all the statistics on every interface of your switches (what? people have switches?), but just throw OpenNMS at your networking management subnet and it'll pick up everything for later review.
You can use OpenNMS for alerting and inventory tracking, but I prefer more extensible tools for those. Just use OpenNMS as a largely hands-off sanity check of your existing monitoring and graphing systems.
https://www.icinga.org/nagios/feature-comparison/