sad to say, but i do think i get same or more pleasing video quality too using my philips 5500s component output. to quote myself also:
i would think so, coz as with my panny ae900 i noticed quite a difference. better upconversion though not necessarily better color or better contrast. as what nerveblocker said above, you should calibrate your source/display to get the colors you want (which may or may not be the correct one). to some, the component output gives more pleasing results.
it's just i might still stay with the hdmi coz i can't bear the hassle of running another three cables as it'll be a cable management nightmare. i already have two surround cables, the hdmi, coaxial for the antenna input and extension cord for the pj.
also, the 600av has better analog audio performance than the above philips.
using full rgb color on hdmi, you get better contrast... but then it looks "video" to me, not cinematic. switching to component color (still on hdmi) gives more pleasing results. if it's a bit washed out, i just lower the brightness a notch either on the pj or the player, or both... and choose between the 3 cinema modes for the better rendition. i also turn down the sharpness to "soft" as even with just the standard setting, there are some objectionable ringing/edge enhancements especially on low bitrate materials.