I have been an iPad user since the first generation and have always loved my iPad, carrying it with me wherever I would go, using it extensively at home and when away from home. When the iPad Mini was announced I knew I'd be getting one, no question about that. Got a black 64 GB WiFi & cellular (AT&T) last week and am just tickled silly with the new little thing! Carrying it with me wherever I go now and she's so much lighter in weight, so much easier to tuck into a purse or bag.... I have all of the same apps on both my iPad 3 and the iPad Mini, with a few different things on the iPhone, and that works well for me. As for comfort and usability: the iPad Mini is great to use when seated comfortably in a chair or on a sofa, or when lying down or reclining somewhere -- the light weight and the smaller physical dimensions make it much easier to handle. @George Lewis: it sounds as though either an iPad Mini or one of the small Windows tablets would be just perfect for you! The tablet form factor is quite different from a laptop in that one does need to hold or support the device in some way, as opposed to having a laptop on your lap with keyboard and monitor both in positions optimal for use. One can type on the iPad Mini either by using its own keyboard or by using an external bluetooth keyboard. I find that I do just fine with the iPad's own keyboard and although I have the wireless BT keyboard, I hardly ever pull it out for use.
The iPad Mini is great for web-surfing, for email, for reading online newspapers, etc. It is also really fun for playing games! I especially enjoy playing Solitaire on my iPad Mini. One can also participate in forums such as this one, and can watch most (not all) YouTube videos, depending on the format. One thing which no iPad or iPhone has is Flash, so that any website or video which is Flash-based is not going to be accessible. That is becoming more and more of a moot point, though, as developers utilize more current options. The iPad Mini is great fun to use any time, anywhere, and can be easily tucked into a bag or even a large pocket, to take along when going out somewhere. One of my primary reasons for buying an iPad Mini although I already had the iPad 3 and an iPhone is that in spite of the smaller size it does what my large iPad does and is easier to read than my iPhone. The iPad Mini also has something really cool that is not included on older iPads or iPhones: Siri. A lot of people really appreciate that feature, as they can talk to their iPad and Siri will respond to questions or will do some simple tasks without the user needing to type anything.
As another member suggested probably the best way to decide if you would benefit from an iPad Mini is to go to a store -- either Apple Store or Best Buy, Target, AT&T, Verizon, etc. -- and handle one and play with it for a while. I wouldn't be surprised if once you've held one, you'd be bringing it home! :)