Here's an update for me. When I'm in class I put my mini in a keyboard case (it was originally for my cheap android device, but the mini fits perfectly on there) since the keyboard doesn't work I just use it to type better on the mini's keyboard. When I'm not in case I use my old netbook sleeve to carry it around in. I'm going to buy a case eventually.
Air stays at home but the r-mini goes out when I go out. I use it to read ebooks, check google news, check weather, take pictures for my daily journal and update my journal too (have it in a keyboard folio) etc. Fits in my jacket pocket or I take it in a leather bag. Don't leave home without it!!!!
I am an Apple devotee. I have and regularly use one of every product category they make save for iMacs (monitor connected to decked out MacBook Pro is fine for me). I have an iPhone, and had first and fourth gen wifi iPads before picking up a Retina mini with LTE - which, as it turns out, is the iPad I have wanted all along.
It goes everywhere. It does not replace my iPhone nor is it so replaced. They are both vital.
iPad1 - it goes pretty much everywhere with me, in my leather man bag
Invaluable on the train commute, used for leisure and work every day. Generally taken on vacation. iCloud integration even more useful as I can work on documents and have them available on whatever device I want, phone, pad, mac.
Have a good friend who downsized to a mini as that would fit into his coat pocket but I prefer the larger screen.