There are other, less costly, alternatives to the Apple IPad and Iphone, primarily those based on the Android operating system, used by many companies. There are also Kindles from Amazon and Nooks from Barnes and Noble. There are both smart phones and tablets. I have had a Nexus 7 sold by Google since July and am quite happy with it, but I have not done international travel with it yet. I can do most things with it that I can do with my Windows laptop, but there is a learning curve to it. If you are already an Apple user, the learning curve for the Apple devices would definitely be shorter. If you are a Windows user, the learning curve for the Android might be shorter.
Both have hundreds, if not thousands of applications (Apps) available for them, a great many of them free and most of the rest quite resonable, with many being added every day. Both types can be used as E-readers for both Amazon Kindle books and Nook books from B&N. Most have cameras and GPSs built in, although I would not abandon my digital comera for the tablet capability,asthe tablets and phones have tiny lenses. The GPS integrates with mapping software, such as Googlee Maps, locating attractions in your area of travel. There are Apps that will locate wi-fi anywhere in the world, although the availablility varies greatly. If you want wider coverage, you will have to go with phone tecnology, 3G or 4G, over wi-fi, but it can get very expensive, but most phones will let you turn off the 3/4G in favor of wi-fi where it is available.
The "7" on my tablet refers to the diagonal measurement of the screen. Most phones are about 4 inches and many tablets, including the Ipad are about 10 inches. I believe that the Ipad mini is about 8 inches. A 7 inch screen is about 3 times the area of a 4 inch, 80% of the area of an 8 inch and half the area of a 10 inch. I have fairlly large hands and wwould find anything larger than a 7 inch awkward.
When I do my trip report/blog of our Costa Rica trip in January, I will definitely have a major section on my Nexus. I will try to do the blog as I go, but time and tablet capabilities may restriict that to an outline of the final product. IMHO, a tablet will be a great tool for traveling with new devices and Apps coming out all the time, and w-fi availablility growing. I have taken my laptop on our las 2 trip, but it's size and relatively short battery life limited its usefulness.