I played both the demo and the retail version and I have noticed some important differences in the retail version, which I'm surprised aren't being discussed more on the message boards. The striking in the retail version is not as fast and frenetic as it felt in the demo. Don't get me wrong, it's still fast but much more fluid than in the demo. And while the AI is still far more aggressive than is accurate, it does not spam the kicks and whatnot to the degree the demo did. With regard to the move sets, they certainly are not simulation accurate but the concerns expressed in the demo about everyone having the same moves or everyone having flashy, highly athletic kicks has proven to be false.
When I played the demo, I was fairly disappointed, but I have been very pleased with the retail version. Historically, I have always been an offline gamer (in part because I am not particularly talented in the eye-to-fingers coordination area, apparently), but I figure now that I have the PS4 I would like to give online gaming a shot. I can tell you I have been thrilled with my online experience with this game. By and large, I have found my online matchups to be fun and challenging. The game really does a good job making striking, clinch, and ground work all feel different and like a viable strategy. Online, I have found that frequently my opponent seems most comfortable with one of those strategies and I find myself reacting and adjusting much as I imagine a real fighter must in these instances. It's really been great.
While the offline AI is still universally too aggressive, I have enjoyed good fights there as well. My one major complaint is the lack of CAF spots and lackluster creation options. Historically being an offline gamer, I was fully prepared to create as many fighters as possible, and had anticipated 40-60 slots. Having only 10 is a big disappointment. In theory you can create a new profile for each division, allowing you to add 10 fighters per division. Unfortunately, with GameFace not providing the quality expected and the lack of body and tattoo options it really isn't possible to create fighters as accurately as I would like. I will likely just wait and hope for DLC to add guys.
But I genuinely recommend you pick the game up if you're on the fence. I feel confident in saying you will like the retail version more than the demo. I really think you'll be happy you did.