Man I picked the guarDUAL start and I'm in love with it. It seemed weak at first compared to the einhander, but after picking helmanship and adding the additional thrusters hullmod I'm running circles around ships and dodging missiles. It feels like I'm just one step away from playing Starsector like I play Ikaruga! One mistake and the little thing is toast, but sneak behind a heavy cruiser's shield and become a hero. So fun. The brilliant part is disabling the small mount and shield in fighter mode and disabling missiles in mecha mode. It works well to make both modes necessary. Only thing I'm missing with this gem is wingmen for the wingcom system, but that's part of the appeal too
The mech mode subsystem definitely feels more useful than the fighter mode one, which does little to enemy shields and is too slow to catch them unprepared. If I had one nitpick I think it would be that it would be fine to remove the charge up time from the fighter's system, because it would just feel more satisfying to use without affecting its power much. As it is it gets passed for the mecha mode one, partly because it's easy to waste it and partly because it slows down flight while it charges up. The charge up time in mecha mode has neither issue: the system seems to work regardless of enemy shields and its own shield makes the loss of mobility less critical.
And if I had another nitpick, piloting the valiant from Diable with Armaaonics is snappier because right mouse click transforms it. Double tap on X is fine but less satisfying. Maybe it'd be better to make the shield turn on automatically when you transform in mecha mode and turn off in fighter mode, since the guarDUAL is so fragile that having no shield on means getting turned into fine paste even by talons rather quick. It's already more efficient to transform and fly off to drop flux in safety than risk taking a hellbore to the face while fiddling with the shield!
Edit: oh right, and in the current version sometimes all weapon autofire turns off (even as it's displayed as being on) after going from fighter mode to mech mode to fighter mode again. They still work manually though.