I want to have the Arduino Uno monitoring a number of different digital sensors that use either I2C or SPI.
With some sensors I am stuck with whatever is available, with other sensors I am offered a choice of using I2C or SPI. The SPI technology appears to be more robust than the I2C. I2C can handle a lot of devices with only two digital pins but there is the overhead of addressing and requirements for acknowledgement plus clocking appears to be more critical. SPI requires four pins plus one additional for each sensor but there is no acknowledgement and the clocking appears to be less critical.
What does experience say? Is it easier to have a number of sensors on I2C or SPI?