I have ran both on my YJ, and I will stick with the Nitros. They seem to have much better ride on and off the trail. For some reason they all push the Hydros on you when ordering though.
They Hydros arent pressurized like the Nitros, it seems like they compress easily, but then the rebound stroke is very slow and in my experience made the ride harsh.
88 Wrangler, Rebuilt I6, NV3550,Atlas 2,B&M Shifter,38/38 Weber, Skyjacker Lift & Nitro Shocks & Stabilizer, Black Diamond Discos, 35 " Regul MT's & Outlaw 2 Alum Wheels, 4.88 Gears, Dana 35 & Super 35 kit & Detroit Soft Locker, Dana 30 & Superior Axles & Detroit Soft Locker & No Disco, SRC Front & Rear Bumpers, SRC Side Armor, Warn XD 9000 I Winch & In Cab Controls, OR Fab Tire & Can Carrier, Rock Hard 4x4 Full Cage, Hood Rack & Hi Lift & AX, Outland Seats, KC & Silverstar.