Ususally a bigger budget means better cg/eyecandy. But it depends on what type of movie it is. Remember, its a business and the owners of said FX company are in it not only to make great looking work but to make money too. However, having a bigger budget for doesn't equal good story. There are...
Okay my two cents... I work in the visual effects industry with people of various disciplines but are all very talented. Despite the progress that CG has made over the years sometimes the suspension of disbelief can go out of the window. It's not so much that the visuals look too fake...