Stick with the console counter part unless you have a Graphics card with over a gig of ram.
GAMEPLAY:
Best in the series. The including of the Rage and Euphoria system was a great decision. Rage doll like physics make even the slightest bump to a NPC look real.
Aiming and shooting has always seemed to be a problem with the GTA series. GTA4 is no exception. I found myself in many situations where Neko would aim at the furthest cop away from him, while the cop standing 10 feet away from me pumps me full of buckshot. While GTA4 does include Simi-free aiming system you'll tend to press down to hard on the right trigger (if you're using the 360 game pads while playing) and lock on to an unintended target.
Driving in Liberty city takes some time to get use to. The Rage engine makes sure every car feels and handles differently. Some cars feel heavy will others feel extremely light. Some people will undoubtedly hate this new feel but it does add to the realism.
GRAPHICS:
Not the pretty's game ever but it still is a looker. It's the amount of detail that'll catch you off guard. Little things like Neko's foot prints in mud (or blood, depending on what you're doing) are just a few things that when put together with the amazing skyline of Liberty City will have you looking for other tidbits of little feature.
Car Damage literally rivals some racing games. Damage is real-time and clipping the under belly of a 747 at the airport will leave you with some car damage that not only makes your Kelly Blue Book value of the car zilch but in some cases make the cars Fenders lock up the tires of the car and make it almost impossible to drive.
Animations are realistic and grab your attention and there is no shortage of activities you'll find pedestrians doing in there free time around Liberty City.
PROFORMACE:
My computer:
Intel Core 2 Quad 6700 @ 3.00 GHz.
4 gigs of ram @ 800 MHz.
NVIDIA 9600GT 512mb @ 750 Core MHz/Ram @ 1000 MHz.
As you can see by my computer falls in the mid range category. GTA4 limits you to how high you can set your graphic sliders. Since my PC only video card only has 512mb I'm limited to the maximum settings. An example of this is lets say I max out my resolution to 1280x 1024x (which is my max setting for my monitor) than I cannot max out my draw distance (stops at 60%) or the Textures (Medium) and this is upsetting because with everything else turned up I'm getting over 50 FPS with little to no slowdown (which to me means I can go higher) This is a problem because textures on medium look terrible.
Even with my high FPS there are way too many pop ups and slow texture rezzing. GTA4 is not optimized and it shows.
CLOSING:
GTA4 is not to be missed. Reason I gave it an 8.5 is because the performance issues. The story, game play and graphics are excellent and even with my performance issues the shear amount of content on the screen make up for it. If you haven't already played the console version I'd suggest picking it up!
NOTE: I don't Rate the Online versions of games