flyingcheesehead
Touchdown! Greaser!
Now I'm looking to essentially just start all over with a new instructor and get my license. The question is is there any reason for safety that I wouldn't want to learn in the DA 40. I plan to rent the da40 once I finish my license. I'm not concerned about the cost difference. My only concern is if it is too squirrelly of a plane to be a newbie pilot in.
For instance if it's too easy to get into a stall or too hard to get out of one excetera.
Having a fair amount of experience in both, the DA40 is exactly the opposite of what you're concerned about. It's one of the safest certified GA planes ever made, and flies *beautifully*.
If anything, I'd recommend you train in the 172 because the DA40 is TOO EASY to fly! It doesn't really "break" at all in a stall and in comparison to the 172 it practically lands itself.
If it's all you're ever going to fly, there's nothing wrong with training in it. However, if you want to fly other types right away, you might be better off training in the 172. Same for glass vs. steam - Train in the harder one, the transition from steam to glass (and from 172 to DA40) is easier than the other way around simply because it takes more effort to fly the 172 and to fly steam gauges.
However - If you're thinking you might just rent one type and eventually buy a Bonanza (such as another poster suggested), I would actually suggest the DA40 would be a better way to execute that scenario. A Bonanza is also relatively easy to fly, what gets people in trouble with them is their speed. The DA40 has a good 20 knots on the 172, or even closer to 40 knots if you're comparing a new DA40 to an old 172 (vs. an older DA40 with a new 172). Because of that, you'd have an easier time transitioning from the DA40 to the Bonanza because you'll be used to a faster airplane already.
Really, you can't go wrong either way, you'll just have a different experience. To me, the most important consideration would be availability during training. If your school has one DA40 and 3, 5, or more 172s, go with the 172. If they've got multiples of both, take your pick.