The SPDIF connections are digital signal output, if you have the option to feed it to a piece of equipment with a matching digital inputs, it's the way to go, if not then use the two analogue outputs. They are not cross compatible, it's a signal like you'd get out of a guitar or mic if using the jacks, it's a binary code using the SPDIF RCA's which has to go through digital to analogue converter to be turned into a signal which is then amplified to drive a speaker or is recorded as digital on some digital equipment. It's then converted back to analogue so you can listen to it. I think most tc helicon stuff runs 24 bit, so you need to be sure it'll be compatible.
Happy new year to you