[Physicist]

The Fuser was pretty neat, do you think it has any credibility?

Yes.

Propellentless propulsion is a holy grail in it's own right, it doesn't need the hype.

Claiming to break Newton's third law constitutes hype, IMHO.

The free-energy guys are claiming to extract energy from some sort of background radiation flux,

Claiming in effect to break the laws of thermodynamics constitutes hype, too. You can have all the energy in the universe, but if you can't get it to flow from a hot reservoir to a cold one, you can't use it to do work. Background energies are almost by definition "cold".

[OBAFGKM]

Dead Dog: Propellentless propulsion is a holy grail in it's own right, it doesn't need the hype.

Physicist: Claiming to break Newton's third law constitutes hype, IMHO.

Newton's laws are approximations in general relativity. In that context, strange things can transpire: Warp Drive. There's a link to Alcubierre's "warp drive" paper on that web page.

Alcubierre demonstrates that, not only does general relativity permit propellentless propulsion, it permits inertialess propulsion to faster-than-light speeds. Stuff of science fiction.

Of course, if you equate propulsion to reaction drives, Physicist is more or less correct. ;o)