The RAM engineer in Matt Maran's video awhile back claimed 1.7 ounces of fuel is burned in 90 seconds with a HEMI... so 1.3 ounces per minute. He also claims "most" people are stopped for about 15 minutes per day. He must be taking an average including dense city folk who are in gridlock traffic, and almost certainly aren't driving fullsize pickups (gotta love marketing). Anyway, let's jkust assume eTorque stops the engine for that duration... every day... you would save 55 gallons of fuel per year, or $110 assuming $2/gal. I am not stopped for 15 minutes per day with the engine off with traffic where I live (obviously this will vary greatly person to person). I would say maybe 2-3 minutes tops in a typical day, and I don't drive every day. The start/stop function works out to be saving 1.7 CENTS PER MINUTE at $2/gal. It's damn near worthless IMO for saving money at stops unless you truly do stop a lot and don't have the HVAC keeping the truck running constantly.
Apart from that, there are other unquantified fuel savings: during gear shifting, and MDS supposedly operating in a larger range. I coud be wrong, but possibly some savings if electricity is generated at 48V since it'd run less amps (and heat), but there may also be a loss since we're converting voltages somewhere to/from 12V for the majority of the truck's systems.
I primarily enjoy the smooth shifting from eTorque (which also saves fuel as mentioned, and some transmission wear). It's also relaxing having the truck be dead smooth/silent when the engine is off at a stop, but other than those 2 things, eTorque goes largely unnoticed. The regen braking feel is pretty minimal, but there if you pay attention. I think it's worth the money right now, but if it proves unreliable long term, my opinion would certainly change.