I've at one point owned each version of the iPad, up until the "iPad" 3rd generation. After upgrading to the 15" Retina Macbook Pro I've found the full size iPad less necessary and am trading back a iPad 3 32GB Wifi for an iPad Mini 32 GB LTE through the Apple Recylcing Program.
The iPad 3 and Retina MacBook Pro are both too close in dimension and features for me to need both. They both have retina screens and are both the "power" version of their respective models.
The combined weight of the Retina Macbook Pro and iPad with Retina Display is 5.9 pounds (4.46 + 1.44). It can be a bit much lugging both around. Combined weight of laptop and iPad Mini is only 5.14 pounds (4.46 +0.68) which may not seem like a big difference but it is definitely noticeable. Also the iPad Mini is much easier to slip into a snowboard jacket, which is a big plus for me.
First world problem, now that I'm running a retina laptop and iPhone I find myself without an on the go device to test non-Retina images. At home the Cinema Displays do the trick, but it will actually be a partial convenience for the iPad Mini to be non-Retina.
If it weren't for recent changes in data plans I'd be getting a WiFi only iPad Mini, but at only $10/mo to add it to my shared data plan I'm sold. I also just got back from spending two weeks in Europe and the ability to use a pre-paid SIM overseas is pretty nice.
The User Agent Problem
Several Web Developers including myself have gripes that Apple decided to use the exact same User-Agent string for the iPad Mini as the iPad 2. I understand Apple's goal is for everything that is designed for a fullsized iPad to work scaled down, but that just isn't always the case especially with small text. I wish Apple would have made the User Agent strings similar, perhaps the iPad Mini being the same but with "Mini" appended at the end.
If there were a solid way to detect the difference between the iPad Mini and the full sized iPad with just CSS Media Queries this wouldn't be an issue. As far as I know, currently this isn't feasible. I have no idea why the iPad Mini reports a device pixel ratio of 1 when really it has 163dpi while the iPad 2 has 132dpi. I can only assume the W3C is terribly afraid of decimals.
Sure it will be great one day when the iPad mini has Retina screen, it will render small type much better for one. For the purposes of what I'll be using an LTE iPad Mini for Retina resolution really isn't crucial. I'll be using it for responsive and mobile testing, the world's coolest in dash car mapping system and maybe even fixing minor bugs from the chairlifts at Mt Hood.