Hmmm... an interesting back-and-forth debate here, with a lot of good points on both sides. Henning, I like your point about more time in your ultimate goal being better. That makes sense - you get to know the plane and its nuances better.
OTOH, there is something to be said about starting out in a trainer and moving up gradually as your skills and knowledge develop. In thinking about it, I see this approach used much more over a wide variety of training regimens... when learning to drive, they don't typically start you out in a Camaro or Mustang, you learn in a compact or small sedan. The counterpoint to this might be pointing out that this might be why you see so many teenagers wrapping the Camaro/Mustang that mommy and daddy bought them as soon as they got their license around a tree. It could be argued that had they been trained in this vehicle from day one, it would be less likely that they would wreck it. Yeah, there might be some truth to that, but at the same time, what would happen if they learned the basics and the rules of the road in the basic car, then got more training in high performance car? Not much data has been compiled on this, I imagine (haven't looked, so I don't know for sure... I'm just speculating here), as additional training isn't a requirement. As an aside, can you imagine how much cheaper our auto insurance would be if people were required to get additional training for each class of car they were going to drive? It is kind of scary to think about the fact that someone who does all of their driving in a Ford Festiva with an automatic tranny is perfectly legal to jump into an F-250 extended cab dualie with a 5-speed manual and a turbo diesel engine without anyone pointing out some of the things to look for when driving the different class of car.
Anyway, I digress. To bring this back to an aviation context, I was talking to an Air Force instructor on the T-1 Jayhawk a few weeks back. He said that for about the first 40-50 hours, Air Force student pilots are learning in DA-20's. If they don't wash out of that training, then they move in to the T-6II, where they first do some simulator rides before getting into the real plane. After about 100 hours of total time (IIRC), students then move to either the T-38 (if they're assigned to fighters) or the T-1 (if they're assigned to transport/cargo/bombers). After quite a bit of time in the T-1/T-38 (I don't remember the precise amount of time), they move into the actual airplane they're assigned to, and begin simulator and in-flight training in those.
Now, I'm no expert on the USAF training regimen, and granted, they are not training any schmuck with money in his/her wallet, but it seems to me that if they are training their pilots incrementally instead of just putting them into the ultimate goal airplane (or tool shed, if they're assigned to fly the UAV's), that should be the model to be emulated. The USAF, and USAAF before them, has been training pilots for a long, long time, and if this is the method they choose to use after years of experience of trying different things, I think that really says something.
Now, all that being said, let me qualify my statements by saying that I am not a CFI, but hope to be one eventually. I'm offering this up as something that seems logical to me, and I'm definitely open to debate on this topic.
To bring this all back around to the original post, I don't see anything wrong with the Cirrus SR-20 as a primary trainer, especially if the ultimate goal is to fly an SR-22. It would be a good platform to learn the basics and the avionics suite early on, then once you have some of the basic knowledge out of the way, you can step up into the big brother. Now, I've never flown either, though I hope to soon, so if someone has flown both, I'd like to hear your take on this suggestion.