Is this gaming PC any good

Yes your pc is good but if I were you i'd get a AMD FX 6300 way more powerful and it will let you run GTA 5 at Very High 1080p 50-60 FPS Settings at this build your probably run it at High Settings with some settings off 30-50 FPS I suggest this: http://pcpartpicker.com/p/6tYB6h also its $15 more for way better performance! Your graphics card is good.
 
You will be able to play GTA V @ 1080p at high settings with like 40-60 fps i think with this setup but you wont be able to enable all the antialiasing stuff and all the extra options besides "normal" settings like textures, shadows and stuff.