I've checked out the reviews on that site as well and consider the review on the 58 CV to be extremely positive - great MTFs in the aperture range used by landscape shooters (which is my main interest), great CA numbers, very low distortion, and a reputation for very low field curvature numbers. The review on the 40 is a little less positive. They don't test as well as Zeiss wide open, that's for sure, so I think most of the excitement is coming from folks more interested in landscape work. A few other reasons they are well received is the build quality (all metal construction and silky smooth manual focussing), the cost (under $400 USD for the 40 and 58, so considerably less expensive than the Zeiss's), and the weight.
Diglloyd's subscription DAP site also reviews them and in his side by side comparisons with the equivalent Zeiss lenses, there's little to fault on them.
Here's a quote from the Photozone review on the 58 - "The sheer resolution potential is unleashed at medium aperture settings where the lens is about as good as it gets today. The level of distortions is negligible in field conditions and lateral CAs as well as vignetting are not much of an issue either. The lens is absolutely beautifully crafted and a joy to use despite the lack of AF." The overexposure issue mentioned in the review was a problem with the early batch, and has been fixed.
