I have one and can't fault it. True their looks are in the 'Beauty in the eye of the beholder' group but the performance is first class.
According to the review in 'Airgunner' Summer 2013 edition these guns actually share some components from other Walther guns, as Hammerli comes under the Walther banner now. Quote ' The truth is, a lot of the parts from Walther's top of the line rifles are also found in the AR20' Unquote.
The gun is functional and basicically does the job that it was intended for. The fact that it is of a 'modular' build allows the end user to customise as they want to relatively simply.
Another point made in the same article was that the gun was in the authors opinion under priced and as such was deemed by many to be not trustworthy, he goes on to say that if the price was pitched at about £1000 then more would have sold. I'm not sure I'd agree to that price tag but do agree that it was possibly underpriced at £600 when it came out.
As said by Rich, it may not be pretty but looks don't put the pellet on the target.