Hi, some folks ask us about the differences and pros/cons between pedalSHIELD UNO and DUE. Im trying to summarize here the most important points:
It is a cool project is you are starting with Arduino and you have interest in audio, guitars, effects and digital music. It is interesting if you dont have much experience soldering electronics as they are simpler than in the DUE.
The general assembly is cheaper than the DUE.
It does not require advanced skills or difficult circuit troubleshooting
The delay time related effects are reduced because of the small amount of RAM of the Arduino UNO.
The PWM output is better in the DUE (it uses proper DACs for it)
It is a nice project if you are a bit familiar with soldering or you build some electronics before. The circuit and general functionality/coding are a bit more complex/advanced than in the UNO.
The amount of effects are bigger than the UNO, specially time related ones.
The Arduino DUE board is very powerful, including loads of RAM and very high speed clock
It is more expensive than the UNO assembly.
It is more difficult to troubleshoot in case that you have problems with the circuit.
In a nutshell, if you are starting and you dont have much experience building electronics, I would recommend to build the pedalSHIELD UNO; it is fun, simple, works, looks cool and it is cheap (specially if you pre-own an old Arduino UNO board).
If you more experience/confidence building electronics and you want to experiment and play with ADCs, DACs and digital signal processing to investigate and learn about digital audio, go for the DUE.