As far as the subject matter goes...
I won't say which is better or talk about pixels or noise or whatever. All of those are so subjective, and it wouldn't stop me from using any of them. I am definitely not a pixel peeper, just someone who strives to take good pics with a convenient tool that is there when I need it and works best for me. I do not like to be without a camera with me at all. I hate that feeling...
So I'll just say how it works for me.
I have two dSLRs, a mirrorless, a point and shoot and an iPhone5. Previously I had an iPhone 3GS but recently upgraded to a 5.
Lately I've been having a ton of fun with the iPhone 5. (The 3GS IMO was pretty bad, but the 5 I find pretty good.) I love how convenient it is and to me, it takes decent pictures and video, too.
Although I always loved that camera (Canon S3IS), I haven't used the point and shoot in probably over a year or more. I'd have to blow the dust off it. For years I carried one in my purse and in fact, it got so beat up I had to buy another. But now it just seems unnecessarily big and bulky for me to carry all the time. Same goes for the backup (ie older) dSLR - don't remember the last time I used it. (Actually, a friend had it for months.)
I used the mirrorless a lot last summer, and a bit in the fall. And I had an outing with the (newer) dSLR and 50-200 over New Years which was very enjoyable and fruitful, lol. Man, I love that camera and lens - they'd have to pry it out of my cold, dead hands if they tried to take it away from me.
Looking forward, I can tell I'll be using the iPhone a lot for everyday snapshots, the dSLR for sports and serious photography, and probably the mirrorless for video and perhaps something in between the iphone and the dSLR, for example during times I need more reach yet still want something portable. Also my DH often uses that even when I have the dSLR.
I also agree that many of the iPhone shots are primarily for social networking and may be pretty bad if put under a microscope, especially in low light. The flash doesn't bother me - in fact the 3GS had no flash so it was definitely missed. I've gotten some really nice pics of my kids using the flash, so I'm not sure I'd say it's unreasonably harsh. To me, many photos come out better using the flash than not, so I do use it a lot. I have softened it on occasion using a tissue, but that's a little trickier on a phone than it is on another type of camera, IME. Getting shots with movement stinks. It just can't focus that fast, and you get blur. But like with other cameras, still life in low light can be improved with know how, although noise can be quite noticable. Still not a deal breaker.