I run Bilsteins 5150 res shocks on my TJ. First the ride is worth the added expense. as for the need, well drive some of Arizona's roads and high speed valving is worth it.
Now with that last statement lets talk about why res style shocks work, multi-valving. most reservoir style shocks have variable valving allowing them to move fluid quickly with short movement and move fluid slower on longer stokes, thus slowing the axle as the bottom drops out when your off road.
Yes this is a basic explanation but ASE booklet on shocks is like 50 pages...
Speed bumps, pot holes, curbs and slow people in the parking lots are no problem for my jeep. And there performance off road was selling point for me.
Whoops and wash boards could be taken a little faster than my old mono style I bought from Tera-flex.
I am just waiting for these to go then I am going to step up to the new 5160's since they are rebuild-able and I can custom change the valving.