I’ve never heard of foam cell shocks until now, had to do a bit of reading on it. Sounds good for on road every day driving but in an off road situation where the suspension is constantly working, it can’t be a good thing. When your shocks fail, you’re relying solely on the springs for your suspension, and that makes your ride bouncy as heck and you’ll bottom out a lot.
I’m not an off roader but from what I’ve learned, oil filled seems like the king. Sometimes old school is best. For on road use, I’d always go for gas.