A rather brief review: It's the follow-up from Street Fighter IV and takes place between the events of SFIV and SFIII.
They carried over the mechanics from SFIV and added the "V-Gauge" system, which can be used for different actions: V-Skills (Attacks unique to a fighter), V-Reverse (counter move while being attacked), V-Shift (a dodge move), V-Triggers (uses the entire V-Gauge to perform a unique attack for a character). I honestly didn't use much of the V-Gauge, but the V-Reverse did come in handy.
The game has a limited story mode along with a survival and training mode. Arcade mode wasn't added until the "Arcade Edition" upgrade a few years after the release. They have a base roster of 16 characters, 4 of which are new (F.A.N.G., Necalli, Laura, and Rashid). Each stage can be interacted with, especially when defeating enemies at the edge of a stage. Online mode is back, with both casual and ranked modes, along with customer battle lounges that can hold up to eight players. However, Team battle is limited to local and is not available online.
There are additional characters, stages, and costumes that can be bought with the season passes (there are six seasons), but they ended up being more expensive than the game itself combined. I just ended up sticking with the base package.
Overall, it felt rough around the edges and not a complete game. The fighting mechanics were sound, and it still was fun, but the gouging with the season passes was a bit much. This version isn't a bad one to play, but it's probably better to get the Championship Edition instead, since it has more content and fixes. Overall, I'm giving it 3.5 stars (around a 7).