I have, and I love it. I have probably around 20 or so hours on it.
It cruises around 130 TAS on avg, and has a much better useful load than the C1 (2 seat version).
In terms of performance specs, I would check out the diamond aircraft website, which will inform you on costs and performance.
The DA40 is by far the most "enjoyable" airplanes that I have flown.
I prefer the DA40 to Cessna 172RG, but I prefer the C172 to the C1. The C1 has very low useful loads, as compared to a 172.