Everything has tradeoffs, and everything depends on use case.
The FEEP thrusters I've seen had a hefty power penalty to keep it on standby, and a long warmup time. Cold gas uses more propellant mass per unit impulse, but it can still come out ahead in total size/weight/power.
The FEEP thrusters I've seen had a hefty power penalty to keep it on standby, and a long warmup time. Cold gas uses more propellant mass per unit impulse, but it can still come out ahead in total size/weight/power.