Point of Existence 2
Not as popular now than it used to be, but there should be at least a few servers with a good number playing.
I too wasn't able to get into Project Reality at all. I know they are not a direct comparison, but I didn't find it anywhere near the quality and fun as Insurgency.
I've used Game-monitor.com in the past to look for mods (well you can find lists of mods easily, but people need to be playing it to bother and that is often a good indicator of the mod quality), so you might try that for other ones.