A couple of articles recapping the online options that will be available for the 3DS version of Super Street Fighter 4 are available. The first one, from IGN, mentions:
To play online in Super SFIV 3D Edition, you select "Internet Versus" from the title screen. You'll be able to select quick match, custom match and friend match. Quick match gets you into a match quickly (hence the name). Custom match lets you specify parameters in your search for an opponent. Friend match lets you select an opponent from your friend list.
The second write up from AndriaSang.com states:
challenge mode and time trial were complete wastes of space. even arcade mode is dumb if it wasn't for the cut scenes
its not the online. i just like the challange. win 20 rounds with only regular moves and ultras with the computers super and ultra bar invisible without losing. to me thats fun cuz you dont know when their special is up. same for time trial. how many people can you beat in a certain time.
Is it just me who finds the 'quick match' feature utterly useless in every game that has it? It takes twice as long to match up with another player as customer searching, and half the time leads to a failed connection anyway. Utterly useless noob feature if you ask me!
I hope the download play allows full use of all characters/stages and not like Mario Kart: DS =="