For What it’s worth;
I currently own a 2006 SR22 SE GTS and I love it… A year ago I transitioned from a 2002 Diamond DA40 to the Cirrus SR22… For my mission, mainly business and 500nm flights, the Cirrus is an absolute “no brainer”. I trained in the SR20, it and the DA40 are similar in climb… Just go fly both and form your own opinion… We all sometimes get too caught up in the numbers… They are both really good modern aircraft…
Things you should consider:
Diamond DA40’s ( io360 - 4 cylinder, bullet proof) have a near 40’ wing span, finding a hangar to fit it into can be difficult… The Diamond will be less expensive to fly , from fuel to Annuals and even insurance…with slight variances… The Diamond requires a rather expensive annual every 5th year,( not sure how many years) $8000 to $10,000 for rudder cable replacement among other items mandatory items, wing removal etc… Just make sure you calculate that into your purchase or that it’s been done prior to your purchase… As to the “FUN FACTOR” - Diamond wins easily, in my opinion. Flying the “stick” is very intuitive and very fun indeed and it lacks all the springs the Cirrus aircraft stick controls are known for (numb feed back)… Lots of articles on this… A negative for the Diamond is it’s wing load… That is to say it’s a bit more bouncy in the air… On warm convective days it’s very noticeable. Not so much in the Cirrus, a bit more stable… The Cirrus is also a bit more predictable in cross wind landings… Although, both are relatively easy to land…
Visibility is ridiculous out of the Diamond - The basic feel is that you’re on a sheet of Plywood with UN-restricted visibility… Does “Magic Carpet Ride” ring a bell… For some it can be intimidating. You sit forward of the wing so you’re able to look and see straight down and of course all around… Because of the Canopy design, the big bubble, you’re gonna get the “Green House” effect… Hot real quick… But, I always thought it was manageable… The canopy can be cracked for Taxi and run-up… Just make sure its closed & locked before take-off. I once took off with it open and had to make a quick return… FLY THE AIRPLANE first…
For a really thorough DIAMOND review click here Trying to find a DA40 that’s not been in a flight school may be difficult… Get a very thorough PRE-Purchase inspection or better yet get an Annual as part of the sale for either aircraft.
The Cirrus SR20 ( io360 - 6 cylinder - super smooth) is - Comfortable - Capable - Better for longer trips… Roomier… Adjustable seats and so on… A far better platform for the utility of going from point A to B… As a mode of transportation the Cirrus, for me is “IT”…albeit subjective… The Cirrus is a bigger aircraft with a slightly narrower wing span. The SR20 vs DA40 Speed, about the same… (My aircraft is the 22) The SR2x requires chute re-pack every 10 years at a cost of $11k to $14k
I cannot stress enough to continue seeking opinions from all the sources/people on this website… The are so many informed individuals that know far more than I do about the Cirrus platform. My experience is that they all freely share their considerable knowledge… Lastly, always perform thorough and exhaustive research, it always pays off…

If you get closer to making a decision on a Diamond DA40 I may be of further assistance…I have extensive knowledge of that aircraft… Please do not hesitate.
Good luck
Kind Regards,
Brad Marlin