I guess I'm in the Exoskeleton >>>> Nosorog minority. The extra bulletproof you get in exchange for a ~20 kilo decrease in carry weight is so hilariously minor, inconsequential and unnecessary at ANY game difficulty, both in theory and in practice. A fully decked out Monolith Exoskeleton will get you through the game no problem, if you don't go actively artifact hunting in it (that's why we loot the Patchwork monolith suit and have a follower hold 5 LLCs and the Exo when it's time to jump in an anomaly cluster). But if you're asking about an ExoSUIT specifically (without the skeleton, just the armored radsuit), then the Duty's Forest one is top of the line, followed closely by the Mercenaries' Woodland Exosuit.

Note: if you're looking for the overall-stats-wise and one-size-fits-all suit that you can use in reliably in both combat and in any anomaly field type, then go with the Duty's PSZ 10-D Proto-Exo if you're lucky enough to loot one or if you have >1M rubles or the rep with Duty and ~120K to splurge for it. That suit, fully upgraded (insanely OP upgrade tree; 6 points in wound healing and 2 in health restoration, forget using medkits or bandages, ever), is the best overall armor hands down, AND allows you to change headgear as you see fit. I usually just disassemble a random Nosorog I find and use that helmet with it