A while back I probably would've said the differences would likely be minimal. But, a couple years ago I was making an ammo order from Sportsmansguide, for some economical S&B hollow point 9mm's, and called a shootin' buddy to see if he wanted me to toss a couple boxes for him in on my order, and I did.
Well, this buddy had 3 different ranges on his property, and had a particular enthusiasm for testing the ballistics of various rounds, by shooting through multiple milk jugs filled with water, and hunting down the round ( it was always fun, and sometimes very illustrative)
Anyway, what we found out about these Sellier & Belot hollow points was that they hardly expanded AT ALL (in that medium). he showed me some other brands that had expanded beautifully. I forget what they were, (probably just Remmy or Winny HP's) but they were also just basic, lower-end stuff, no Gold Dots, Hornadys, Golden Sabres, or anything like that, yet they expanded very nicely, especially in contrast to the nearly non-existent expansion of those S&B's.
So, yeah, there very well may be a difference.