A very good game that challenges you.
On the graphics side of things Socom 4 doesn't have best in class graphics but they're still pretty darn good. The look and feel of them defiantly reflects a sense that the developers made a conscious effort to give players a game that would make good use of the Playstation 3 hardware with varied environments and such. The environments themselves strike a good balance between jungle and urban type conflict zones.
On the gameplay side of things Socom 4 plays much like you standard run of the mill 3rd person shooter with cover mechanics. However don't mistake this as your typical you do all the heavy lifting and a majority of the killing kind of deal because you'll have access to 2 man units under your command and it is essential that you utilize them to the fullest extent. This is because the AI is smart and aggressive and while your foes may sometimes come straight toward you they make good use of cover and will flank you if they see a way to get the upper hand. This level of aggressiveness and intelligence makes it a challenge and really forces you to make good use of your team. At same time you also get a unique little bonus of your own in that you can level up your guns up to level 5. You do this by killing enemies and with each level you unlock additional things for your weapon of choice which get automatically applied at the start of a mission and can be tweaked from the weapon selection screen. However if you want more guns you're going to need to pick them up off of dead enemies and finish the mission or level your on with them as part of your load out and trick is that you can only carry 2 guns.
Multiplayer wise Socom 4 is pretty good for the most part with a decent selection of maps and a pretty good selection of game modes to take part in. New copy's come with a code for Socom Pro which gives you access to some additional content otherwise if you buy the game used and you want access to Socom pro it costs a ridiculous $15. Otherwise it's hard to say if it is an online pass or just a promotion thing for additional content.
As a whole Socom 4 is a challenging game and while it may not be a high quality shooter it is still an enjoyable game for those that are looking for a challenging shooter.