The best? No, they are one option for endgame builds but there are alternatives of course. All the energy types except AP can spawn with superior mods, namely Accx3. A purple Mk XII one of these is hard to beat. Another solid option is the Galor's Spiral Wave, the only weapon so far with 2 procs (disruptor and phaser) and 4 mods (Accx2 Dmgx2). Romulan plasma beams with the experimental beam and the correct console and gear setup can yield the highest beam DPS in the game.