Desktop would be my choice because I've a brother who builds PC and i also have some knowledge about it. Laptops will always be more prone to danger because of its mobility and keep in mind that this device are our investment. We needed to keep it safe and secure. My point is that if you know your need into computers invest more on desktop. It usually last longer.
Together with my thesis partner, we developed a deaf and mute translator device using the arduino pro mini. We also use flex sensors and gyroscope for this system. If you need to develop small or miniaturize project, i would recommend this product, Arduino micro and Arduino nano. One disadvantage using the Arduino pro mini is that you need to purchase a loader which is cp2102, download and install the driver in order to load the program successfully.