I have an Instax 100 and 200. The 200/210 are indeed very cheaply made (the 100 is a little more sturdy), and overriding the flash is a very inexact science... however, people absolutely adore them, the output can be great, and they seem much more friendly than a big DSLR. They are pretty big cameras, but it's proportional to the size of the final photo.
The Instax film itself is pretty good, whereas some of the Impossible Project Polaroid film can feel a touch experimental at times.