i have the video component cable and never use it on a good tv or monitor but i belive you can get some good quality if your's monitor acept progresive scan. i use my psp go in an old model television,never used the progresive scan option =/
From what I can see and tell, for PSP games, the video output is a 1:1 pixel output.
But strangely, for PSX games, it's stretched to full screen... Depending on the game, this can look pretty crappy. I just wish some of the video output modes that you can get for the PSX games on the PSP were also available or applicable when using the video out. Seriously, what were they thinking?!