Challenging.
Now, you might reasonably expect that after playing at least three matches in a row with these PUGs I would remember their names, but alas, all I can recall is that one had "caffeine" (or maybe "coffee"?) in his name, and the other was something like "apolls". Everyone equipped, everyone was trying hard. Every match I was out of gels and/or ops packs by wave 8, and so were they.
We did Rio/Collectors, and for objectives had the long escort, the EZ hack, and the central tower hack. EZ hack was brutal. Actually that whole match was brutal; revive circles were common, being revived into a pile of scion grenades was routine. For extraction I suppressed the spawn next to the EZ while the rest started by holding the tower and slowly fell back to the EZ, which actually worked quite well, full extraction.
Hazard Reactor/Cerberus was next. Wave 10 was pizza, easy right? Except it seemed like every single delivery route was being blocked by an Atlas with 2-3 phantoms flanking you. Wiped.
Finally, London/Geth. Thankfully the wave 6 and 10 objectives were both targets. They still didn't make it easy, but we extracted.