Well, from what I've seen, there would be no real difference. If the Beam Sabers in Gundam have the same qualities as Energy shields (a la G-Savior), they'd be able to deflect energy weapons, similar to lightsabers.

The only major difference would be, could you change the width of the beam (a la Gundam, see Epyon or GP02 for ex) or the length (as can be done in Starwars).

*grins*