Main point of contention is obviously the price, I picked mine up for £34.99 for a digital code, and it's still pretty dam high, this was a £19.99 game at most, they didn't add enough to justify the price.
Probably the biggest, and most interesting edition is a 275+ art-book, each with lavishly detailed concept art from SFII through to newer titles.
Outside of that you have violent Ken and a color pallet changer, that doesn't really add much. Most of this is stuff seen from the Playstation release, don't be fooled into thinking this is new, because it ain't. It's a re-release essentially, with an extortionate price.
Ignoring that, 25+ years is, at it's core it's still playable as ever, and has an online community, albeit small.
Best holding off until it drops in price.