The Ergo "Delta" grips. Unconventional, yes. Ugly, beauty is as beauty does. Do they work, absolutely!
When these were first introduced about 1 1/2 years ago most posters severely flamed them with ever even seeing them in person, let alone handled or shot a gun with them installed! The first response (post 2) above is typical of what was seen previously.
I put a set on my 640-1 as soon as I could get a set. They are comfortable, they work, and best of all keep your middle finger knuckle from being battered by the trigger guard, definitely a positive. I just wish they would make a variation that extends all the way up the frame knuckle of the 640 style frame! Other colors maybe too.
I recommend to anyone who is tempted to be negative about these to buy a set and try them! They are only $20, bet you have spent more for other accessories that are rarely if ever used anymore!