I've been up in the platform while firing, but I've never seen the results from the ground. It's pretty impressive even from up there.
A friend of mine was a AFSOC JTAC, and served in Iraq. He's not easily impressed, and even he spoke of how intimidating/impressive it was to be on the ground, danger-close, and having Spooky open up.
He had to do call them in one time from a rooftop in an urban area. The fire from the gunship saved their ass, but even he admitted it was damned hairy (not to mention nearly deafening) to be sitting there, heads down, and having the 130 tear up everything around them. It was intimidating... and they weren't even the target.
As far as close-air-support goes, the precision, armament, and loiter time of the AC-130 are basically unmatched.