Your HDMI to composite video converter is within the scope of the HDMI adopters agreement because it limits the output to 480i or 480p.
The HDMI to component video converters that you listed are outside of the scope of the HDMI adopters agreement because it can output HD on a non-secure component video output. It's the reason you don't see HD component video outputs on Blu-Ray players anymore (or pretty much any type of component video output). In my opinion that is a poor choice by the HDMI Org (and its member companies) because your usage for a component video output is a valid use. However, no one asked me.
So, I'm going to keep from commenting on the particular units you posted other than to say for those to work they would have to be HDCP compliant and their keys would have to not be revoked. Keep in mind that often once the HDMI Org sees references to these type of units, they seem to disappear from the marketplace quickly.
Now to your question, you're taking 1080i or 720p video and removing about 75% of the information to go to 480i. Then with composite video you are combining the three RGB video signals from the source into a combined brightness and color signal. Basically you are taking HD and converting back to NTSC (Never The Same Color). So, you are losing a lot of information.
If you go to component video, you are no longer combining the three video signals. But, you're still losing 75% of the information.
On the other hand, your old Sony is not anywhere as sharp as a current TV. Color will also not be as accurate. Your one advantage over a current TV is that your black levels are better than any LCD or plasma being produced. So, if black levels are important to you, then component may be advantageous. Otherwise, it probably isn't worth the effort and chance that you'll need to try multiple converters before you can get one to work.
My initial reaction to your question was save your money for a new TV. I think after writing all of the above, that's still my opinion.