What would you like to know? I have about 300 hours in Cirrus SR 20/22 and about 300 in DA-20/40s. The SR-20 is very comfortable, cruises at 155 ktas but suffers from pathetic climb performance and has no short or soft field capability. The Cirrus, particularly the avionics, look great but have proven to be relatively unreliable.
The DA-40 is easier to fly, cruises at 140 ktas, and has marginally better climb performance. The Diamonds have proven to be very reliable and the Garmin G1000 seems much more reliable and robust than the Avidyne. Unfortunately the DA-40 is uncomfortable; it's hot, cramped, and the seats lack padding and do not adjust.
If I had a choice between a SR-20 and a DA-40, I would pick... a new Cessna 182 with the G1000 suite. Even though it is a 50 year old design, it carries more, farther, in more comfort than either the DA-20 or SR-20. It has good short and soft field performance, is incredibly easy to fly, and is statistically the safest GA plane ever built.