The people behind Wiring must have been a bit jealous of this success achieved by others with their work so they started simplifying too. The result is the brand new Wiring S board that is almost the same size as an Arduino Uno. The Wiring S team apparently decided that they wanted to do things slightly different than the Arduino team, so the board looks a lot like an Arduino, but it is not compatible. Where Arduino uses mostly ATmegaXX8 controllers, the Wiring S board is based on an ATmegaXX4 controller (ATmega644 on my 1.0 board). The connectors look very similar, and are positioned in a similar way, but there are 5 instead of 4 and the pin-out is different. Also the project is open hardware, but the design files are in KiCAD instead of Eagle.
It is rather interesting to see how Arduino is becoming more and more complex with programmable USB interface chips, all kinds of different processors and more connectors whereas the Wiring S board is almost like an old Arduino Diecimila but with a bigger processor. The board even offers the possibility to replace the FTDI USB/serial converter chip by an FTDI cable which brings it very close to the even older Arduino Serial. The two teams seem to be working in opposite directions.
For the people who would like to have the best of both worlds, they should use Wiring because the Wiring environment is capable of handling Arduino boards, whereas the Arduino environment does not handle Wiring boards and a Wring Play Shield is available that allows you to stick Arduino shields on the Wiring S board.
The Wiring S board is simply rectangular with its extension connectors on a 0,1� grid and 4 mounting holes placed in a logical manner. I do not like the position or the shape of the reset button; it is too hard & difficult to press. The solder side of my board was not cleansed properly and this seemed to be true for the whole batch received by my distributor. Maybe this is a pre-series problem?
Will the Wiring S meet with the same success as Arduino? Hard to say, I guess not, it is probably too late now.