I'm sure some of you probably already know this but I haven't personally seen it mentioned.
u334 b34, while functionally identical, seem to have different hitboxes. The 4 of u334 seems to have a larger hitbox than the 4 in b34 and is less likely to wiff. At point blank range, the 4 in u334 connected for me about 95% of the time where it never connected with b34. They both stop connecting completely after you get beyond a certain range, though.
Not exactly the most useful information, but information none the less.