Compilation of the first three Street Fighter II games: Street Fighter II, Street Fighter II: Champion Edition, and Street Fighter II Turbo. They play well, with just brief loading screens between matches.
Not sure about the others but while it is otherwise like the US arcade version, Champion Edition has the character move changes that were found only in the Japanese arcade version, such as Balrog's Turn Around Punch having multiple charging levels, his Dash Punch hitting crouching characters, and all of Sagat's Tiger Uppercuts causing knockdown, rather than just the light one. And it has a training mode. There's also a Versus mode, requiring two controllers to be plugged in--there's no VS CPU option in Versus or Training modes.
Ryu's light punch in Collection 2's version of Champion Edition has an input delay--as measured in my incredibly crude cell phone footage way--of about 4 frames, occasionally dipping to 3 frames. (Compare with CE in Street Fighter 30th Anniversary Collection on PS4 (see entry 1368), where I measure a delay of 5 frames, occasionally rising to 6 frames.)