No que toca ao ecrã, usem um iPhone (ecrã capcitivo) e depois usem um PDA qualquer, mesmo os com "touchflow", com ecrã resisitivo.
Axo que as diferenças vão saltar à vista... e ao toque.
Capacitive: A capacitive touch screen panel is coated with a material that stores electrical charges. When the panel is touched, a small amount of charge is drawn to the point of contact. Circuits located at each corner of the panel measure the charge and send the information to the controller for processing. Capacitive touch screen panels must be touched with a finger unlike resistive and surface wave panels that can use fingers and stylus. Capacitive touch screens are not affected by outside elements and have high clarity.
Resistive: A resistive touch screen panel is coated with a thin metallic electrically conductive and resistive layer that causes a change in the electrical current which is registered as a touch event and sent to the controller for processing. Resistive touch screen panels are generally more affordable but offer only 75% clarity and the layer can be damaged by sharp objects. Resistive touch screen panels are not affected by outside elements such as dust or water.
Fonte:
http://ubertablet.blogspot.com/2006/04/position-vacant-thoughtful-software.html
Three types of touchscreens are available based on three different technologies.
Capacitive Touch Screen
In the capacitive touch screens, the screens are made up of a glass panel that is covered with a material. The property of the material is that it can store electrical charge. So the capacitive touchscreens store charge. Human body can also store charge. When you touch a screen with a finger, some of the charge gets transferred to the finger. The circuits at the corner of the system sense this decrease in the charge on screen. Capacitive touch screen system measures the relative difference at each corner and the spot where touch occurred, and then switches the specified information to the touchscreen driver software.
Resistive Touch Screen
The resistive touch screens also made up of normal glass panels. The glass panel is coated with three layers. The two layers conductive and resistive are kept apart with spacers. The third scratch-resistant layer covers the whole setup. When the resistive touch screen system is running, current flows through these layers. On a finger touch, the two layers get connected and change in electrical field occurs. The system calculates the coordinates of point of contact and passes them to touch screen driver software.
SAW Touch Screen
SAW (surface acoustic wave) Touch screens uses reflectors and transducers for sensing the touch. One transducer is placed along glass panel's X-axis as a receiver and one along Y-axis as transmitter. Reflectors are placed on the panel as well. Transmitter emits ultrasonic waves to receiver. Touching the panel absorbs the waves and system notes the position of touched event. The information is send to processing unit and touch screen driver software.
Fonte:
http://www.embedsystems.com/devices/touch-screen
Para quem não quiser ler tudo ou traduzir, os factos são estes o ecrão capacitivo é ligeiramente melhor de facto é, em termos de sensibilidade, será assim uma diferença abismal? NÃO!! Ambos os ecrãs funcionam de maneira idêntica e o ecrã resistitivo ainda tem a vantagem (dependendo do ponto de vista) de puder ser manuseado com um "pointing device". A nível de utilizador final qual será melhor tecnologia? Depende, se gostar de estar na moda e gostar de possuir um aparelho " phone wanna be", então deve escolher a tecnologia vendida pela maçã, se for um utilizador que dê valor á evolução tecnológica e que queira ter um aparelho que faz aquilo a que se propõe então a escolha será um PDA com características idênticas a este ou similares de outras marcas.
Acho que as pessoas ao darem a sua opinião deviam por de lado fanitismos exagerados, e não defenderem uma marca como se não houvesse amanhã ( a não ser que seja representante dessa marca).
Um abraço para todos.