I went for the harbinger nodes out of some insanity, it's actually paid off fairly well, had 2 ex from ex shards and a ton of other currency just from regular mapping.
But is it worth waiting 3 secs between harbinger waves? That's like 6 seconds of waiting every harbinger.
Do the different shards stack properly now at least?
I agree the atlas passives seem very cool, can't wait to reach end game! I was gonna go for shrines, but going through campaign reminded me that most shrines are lightning or shock nova, and those are just dull. Now I'm considering other stuff. The niko node that gives +1% ele res cap per sulphite node (and some other boons) taken seems really good if you can trigger it for various bosses (or megajuiced archnemeses). Just the map progression stuff seems real nice.