I go off my eyes and VGA has a sharper cleaner look for games for than HDMI, I will listen to the technicalities, but in the end I go with what I see and VGA looks better to me than HDMI for games.
I guess depending on the quality of your old crt, then yes you might get a "cleaner" picture, but with newer/current monitors that support hdmi/dvi, vga isn't going to cut it, especially past the 720p perspective (where 640x480 is its standard).
Also, I've looked at comparisons and generally the higher resolutions (ie 720p-1080p+) vga degrades exponentially, considering that vga is analog, while dvi/hdmi a is digital signal, [to quote wikipedias artical]
"It is designed for carrying uncompressed digital video data to a display."
"Previous standards such as the analog VGA were designed for CRT-based devices and thus did not use discrete time display addressing. As the analog source transmits each horizontal line of the image, it varies its output voltage to represent the desired brightness. In a CRT device, this is used to vary the intensity of the scanning beam as it moves across the screen."
Take it as you like :/