a) Composite video is not capable of providing high enough image quality to get sharp pictures in anything higher than "lo res" mode. The old addage, "Garbage In, Garbage Out" applies here.
b) Many of these "VGA converters" are of questionable design quality in that they "drop frames" to compensate for differences in scan rate, or have a relatively slow input sample rate to begin with. This is fine for average quality video use (watching television, VHS, or DVD movies) because a few frame discrepancies here and there will never be noticed. When using the AMIGA, however (especially in interlaced display modes) it can cause a mutltitude of undesirable characteristics in the display. This is most predominant in animations, fast movement of objects on screen, and some games/demos which employ hardware tricks that rely on close timing of the video hardware..
c)There is also the question of how the device handles features commonly employed by AMIGA display modes such as large overscan area, etc.
If possible, with any third party "scan converter" device, I would "try before you buy" and make sure that it is going to produce acceptable results in all of the AMIGA display modes that you plan to use.
About the best "scan doubler/deinterlacer" solutions I have seen are the A3000's internal VGA output, and the ICD "add flicker free video 2". Both of these produce rock-solid "1:1 framerate conversions" in both interlaced and non-interlaced modes with full overscan. Even these devices, however, do exhibit some "image separation" characteristics with fast moving on-screen objects in interlaced modes. They do it in a very tolerable manner, but it just goes to show that there is no "perfect solution"..
