Soulcalibur 4 is a good game for the facts that it's pretty, you can customize characters, you can play as darth vader(brain explosion), and you can play online but other than that all other elements are anywhere from okay to mediocre.
The gameplay is almost exactly the same as even soul calibur 2 which is the latest soul calibur game I've played. It has many of the same problems as the old games or maybe you'd consider them traditions, those are that the combat never looks natural, there are a few times in particular where given common sense what you did looked like a hit but for whatever reason doesn't work, also it's kind of annoying to see characters grab at the air. The other thing of course is it is by some standards a button masher, or rather it gives you the option to button mash when you play easy matches against the computer but you can still get pretty far just by alternating the 3 attack buttons randomly. The strategic part of the game that exists in the character customization can be satisfying however it's really hard to figure out exactly what you're doing so people will most likely just choose whatever makes your stats go up the most and forget about all the different skills.
The driving goals are admittedly not going to make you tear up or anything but they're okay, you can play a story mode which will take you all of 10 minutes to complete and will give you an interesting story about each character and even short cutscenes at the end, they're all in engine of course and so they aren't that great. So all together unless you play through over and over that could run you for about 4-6 hours but trust me it's not worth it. You could also play in arcade mode which when completed gets you 10,000 gold which is less than you usually get in story mode and it's quite a bit more difficult so if you really wanted to grind then this mode is useless except for casual once so often playing. There is the tower of lost souls mode which is basically a series of random battles that get harder and harder and have hidden items although to get them you basically need to look it up online, these battles will force you to customize your character at some point as the difficulty will hit your limit after a certain point but you usually have enough money to compensate for your lack of skill and combined with practice pretty much anyone can beat this mode although it is the most meaty part of the game time wise. The star wars stuff just pisses me off, you will have to defeat the apprentice as darth vader to unlock him which is an achievement but then when you play as him he's not all that special so it feels like they just jacked up the difficulty slider and told the computer to mash force powers because they wanted him to look really cool so their friends at lucas arts could sell their game, well I'm not buying it!
The online unfortunately is not very well set up. The basic way you choose matches are either ranked matches or player matches and then a basic battle 1 on 1 or a special battle that lets you use your custom characters or special clothes for existing characters with 1-4 characters. The way you actually start matches though is unreliable, you can hit quick match but unless you've got a crazy fast connection there is no way you will ever start a match that way. You could choose custom match but again that's even slower so that's unlikely. So it seems unless you have a T1 or higher connection you will have to host the match yourself or at least that's the only way you can do it reliably. For that matter though unless you've got T1 you might want to avoid online because anyone who does is going to cream you as your moves will take a long time to be executed while they will be able to react at lightning speed. This all seems like it could of been fixed just by having a different place for people with slower connections.
That said though if you do manage to win a few matches either because you have a fast connection or because you're just that good it can be satisfying to see your little experience bar go up and see yourself rise up the levels, but if you're trying to do anything but that, no luck, the game doesn't reward you with anything other than these rank credits so you're still going to have to play single player if you want to customize your characters more.
There is the skill level for characters that can be developed whenever you play as them but in general all this does is unlock some slightly tweaked weapons every few levels.
So I think I've illustrated that there is a lot to do in Soul Calibur 4 the only problem is how much do you like the game in the first place and are you willing to do many of the same things over and over again. If so then this game could occupy you for quite some time just don't expect it to replace the online experience in games like resistance call of duty 4 or warhawk.