Tele-convertor lenses for A610/A620/A630/A640 and the G6/G5/G3

[lathe]

I have found the following lens available for the A610/A620/A630/A640 and the G6/G5/G3 which I think are all compatible cameras (as far as tele-convertors go). I was wondering if people could give feedback on their experiences with these lenses and if there are any lens I have overlooked. I'm looking at getting a teleconvertor lens for my A640. Most of the comments are from a lensmateonline review of A610/A620 lens.

Opteka 12888 (3.0X)
Raynox DCR-2020PRO (2.2X) "Slight vignetting on A640." (Raynox offical doc) "The most powerful here, but somewhat edge soft. Noticeable pincushion distortion." (on A620)
Opteka 61781 (2.2X)
Kenko KNT-20 (2.0X) "The Kenko performed better on the G3/5/6 - a bit softer here." (on A620)
Tiffen (2.0X) "Excellent image quality, 43mm thread mount. Use with our 52mm Lensmate adapter and a slim 52-43 step down ring for best results. (This lens discontinued by Tiffen)" (on 620)
Opteka 35456 (2.0X)
Raynox DCR-1850PRO (1.85X)
Canon TC-DC58N (1.75X)"Our samples show soft corners/edges and strong CA." (on A620)
Olympus TCON-17 (1.7X) "Same superb image quality expected from this teleconverter." (on A620)
Raynox DCR-1540PRO (1.54X) "Very good all around performance in a compact lens design." (on A620)
PCEC Auto iS (1.5X)

[SpecialK]

I had the wide (.7x) and tele (1.75x) Canon brand converters and the Opteka .45x and 3.2x converters.

Canon was fair-to-good, though they soften the image and contrast somewhat. They were $79 and $85, I think.

Opteka has poor quality lenses, though they only cost $29.99 each and come with aluminum adaptors. They really have a lot of rainbow fringing, and only the central 1/3 even even close to sharp.

I know nothing about the others you list.

[lathe]

Thanks SpecialK for great the info.

Anyone else have experience with some of the lenses?