I've never been very good at fighting games but I do enjoy playing them.  I never played fighting games in the arcade growing up either.  I tented to play FPS mostly with the occasional RPG.  So my experience with SF4 may be very different than one of the purest who've been a fan of the series from the beginning.  So far I have to say the game is absolutely beautifully drawn and the net code has been excellent.  There has been no log in any of the matches I've played.

There is a wide variety of characters to choose from when you start playing the game.  Like any fighter there are all the typical modes you'd expect to find in a fighting game.  The one interesting addition is the Arcade mode which allows you to play the story mode of a fighter but instead of facing AI you can fight people online.  I'm not sure how this varies from normal online matches but I suspect this is just the better way to find quick matches online.

If you just want to practice against the AI you can disable online match requests in the arcade.  You can then chose the AI difficulty then battle through several rounds of AI matches.  I've been getting my face kicked in during the Arcade matches so I'm not sure how many rounds there are to win Arcade mode.  I've noticed no difference between the difficulty between Easy and Normal so far.

The only flaw I see in the game is the lack of a lobby system.  If you want to party up with a few friends you can't just join a online lobby and wait for the next match.  It seems you can only have 1v1 so there is no way to watch matches online.  I found this to be a bit annoying online since you'd have to sit and wait for a match to begin then get the game invite and join the match.  I am not a huge fan of the default button layouts since it places the heavy punch and kick on the right bumper and trigger.  I was able to customize the layout to swap the light and heavy buttons which makes it harder to throw but makes up for the poor quality of the 360 bumpers.