I own and use two
Ikodot finders on various cameras and find them well worth the asking price.
The main focal length I use them with is 28mm, one is mainly used on a Ricoh GRD and the other alternates between a Leica If/Voigtlander T. However I also particularly like using them with a 21mm and 35mm focal length.
With just a little use the Ikodot is very easy to get used to and I find you quickly develop a physical memory of where you need to place the camera and finder in front of your face to get the appropriate field of view. I have also found that the Ikodot is very good at training your eye for seeing different focal lengths and their field of view before you lift the camera to your face.
As for accuracy, well I find them accurate, but then I am not shooting subjects that require great technical accuracy as I am usually more concerned with the overall composition and for this the Ikodot does the job!
What's with the whining over the price? I had a quick look at Ebay and the price for two completed RASAL finders was $69 and $165, the last surely being collectors item, but in the case of the Ikodot is $100 really that much more for a new item? The RASAL is also a LOT larger and when folded still takes up a great amount of space and is of no use for fields of view wider than 35mm. Plus the RASAL, when unfolded, looks like the aiming device on a stinger missile! The Ikodot in comparison is positively transparent.
The Ikodot is a quality item, incredibly well made, being put out there by a motivated range finder fan who does this in his spare time. He's a great guy to deal with and I think he should be supported. So before you discount this item check out the website, thoroughly, and if you have questions fire off an email to Fritz. Explore the website;
http://www.ikodot.com
And here is an older pic I framed with the Ikodot mounted on my Ricoh GRD;