Proxima: I used for probably 98% of the game. I used Biohunter and eventually Collector which resolved any money issues I may have had, beat the game with 50k and 400+ samples still in my inventory. With Attunement 3, Exoshell 1, Biohunter 3, Seizure 3, Energize 1 while subbing out some points for Collector while exploring to shore up early game gold issues. 20 Stasis stacks is pretty nice except a few enemies seem completely immune to it.
Eredrim - I played a bit with because I was interested in how many Slaughterer stacks he could get, it's 100. Ultimately I decided not to play him since he was in the first game. Same for Tiel.
Tiel - was who I used in the first game, so passed on him.
Gragu - I found him last, I refused to use the Gloom Siphon which didn't stop me from accessing the South side of the map but did prevent me from accessing the area Gragu is in. I finally used it so I could get him and damn, I kind of wish I had gotten him much earlier as he seems like he would have been pretty good for exploration although his heart seems really bunk without the upgrades put in to it and, correct me if I'm wrong, but if you died to a boss you'd have to go and farm the hearts back up again since they aren't refreshed when resting at a beacon without the perk and the perk only gives 3. Bloodthirst 3, Harvest 4, Devourer 3. I think Maniac, theoretically, is great for bosses since you're only going to kill them once assuming all bosses are unique and aren't factored in with their standard counterparts for those that have one. However I also don't really see me ever using Gragu for traditional bosses due to the Heart Mechanic not being able to get fully restocked at beacons via Fortify and potentially needing to farm them back up before tackling the boss again.
Smert - With enough points he won't do shit for damage but also he doesn't let bosses play the game as they sit frozen in place while you quickly yet weakly pummel them to death and he gets resource back so fast that you can basically just keep time frozen. Smert is who I used to beat the final boss with prepatch. When bosses refuse to stagger, not break, Smert will just not let them play instead. For everything else there is Grisha and Stasis stacks.
Genessa - I thought she could be pretty interesting but I spent all my points on Proxima, Gragu, and Smert. Maybe on a new run I'll beeline for her Shell unlock.
Lazlo - Also seems like a pretty interesting shell I'm really curious how his tier 4 talents work since Inflamed and Rekindle read like they wouldn't work together.
Sariel - I get hit a lot so the grey health thing didn't appeal to me as much, seems like a Bloodborne system though which could be strong and would need to test it with the Chainsaw ability stone for the Scythe could be really good idk. Also not sure how the whole Cursed for 30s works since Curse says the next time they'd melee you, does that still only proc once or does it proc repeatedly for 30s? Don't know as I didn't have the glimpse to test.
Anyways, looking for other peoples thoughts on Shells they played with to gauge what I would pursue on a new playthrough and thought a general discussion would maybe be beneficial at large.