Duh...
Old A (MS-130A) is better with its folding mechanism.
New-A is better because it doen't have rear fork welded, it only has dropouts.
Without any foldy/reinforcement mods (for lazy boys), then take the OLD-A .
If you are into modding, then you could:
a) put B-foldy to new-A deck
b) reinforce new-A's foldy with some two custom thicker bigger and wider steel plates (4 millimeters thick at least, one plate in the deck, one plate between the foldy and deck.