I would agree with pretty much all guppy's summary apart from the fact that reverse is purly a drag thing.
The garretts can throw serious amounts of air forward. Enough to throw a ground handler on his arse when taking out the prop locks.
That's exactly what drag is! Drag is a force that acts rearward to an airplanes direction of flight. Ignoring the slight angle between the thrust/reverse line and flight path line, a reversing propeller is purely a drag thing.