As you can see, size does matter. Generally I would agree with the other posts.
I'm also not a fan of the standard 55 gal tank. It's just too thin, front to back. On larger tanks, look for ones that are 18 inches wide, or wider.
To get back to the original post, about a 14 gal biocube. These smaller tanks can be real gems, especially if they are set up so that you can view it up close. However, due to their size they have many limitations. You will be limited to one or two small fish or shrimp, some corals, and a clean up crew. You will need to avoid livestock that just can't be kept in small tanks. As pointed out a small system has very little margin for error.
If you keep in mind the limitations a small system has, and you are sure you'll be content with them, then such a system may be for you.