Fission-Fragment Rocket

> With exhaust velocities of 3% - 5% the speed of light and efficiencies up to 90%, the [dusty plasma] rocket should be able to achieve over 1,000,000 sec Isp.

It's plausible to build a spacecraft with delta-V equal to 2x its exhaust velocity. So if that rocket is feasible then you're talking about a serious interstellar drive, especially if you can boost the acceleration phase with something like a laser sail.

That being said, fusion propulsion is probably still preferable since light elements should be easier to collect than heavy metal nanoparticles.