GSM / GPRS Shield Wireless Extension Board Module w/ Antenna / Adapter for Arduino

Pros: Easy to use. Works out of the Box. Nice Package. Very cheap and good build quality. Can find several tutorials on the internet. Comes with the 9V 1A power supply. Comes with the antena. You can use the hardware serial and software serial by just changing some jumpers. Led activity is very good

Cons: The SIM card tray could be more sturdy.

Other: DX have the best price for this kind of item. It can be used with any microcontroler or even with your computer serial port USART

Pros: The module comes from the elecfreaks GSM module. They have a tutorial on how to set it up and some examples on how to use it using the arduino platform. Comes with the required power supply to make it work. Has SMS, GPRS and audio (phone calls).

Cons: The sim card holder is not so good but it works. The elecfreaks page has a lower price for it.

Other: The module is easy to use due the tutorials and works perfectly. It could be a bit cheaper.

Pros: Full support of manufacturer's commands module. Excellent compatibility with the Arduino. Good documentation on the website Elecfreaks. Using small sketches, almost anyone can build an alarm, or remote control, data transmission. Anything on GSM. GPRS connections are also possible.

Cons: Soldering of components is not accurate-the soldering flux to the bosses remain Board. Although the quality of the PCB is good. The price might be lowest, because mass production of GSM modules is enormous.

Other: Very happy with purchase. I implemented the planned with ease, which was previously not available to me.