I have met a few ppl that have done that. We currently have an Inf Cpl that is just finishing up the RegForce Dp1 course.
The work when on exercise/deployment is most times harder. For the Inf is more routine; the Eng could get many different tasks. When we finish one we usually have several others waiting. We go on an Op with the Inf and when we come back the Inf settles on a sentry/security routine while the Eng get to improve the roads, defences, dig ditches, shitters, shelters, water, electrical, etc.
However, you get to use explosives, many tools, could learn Hvy Equipment, diving, etc. Our areas of the FOB or when we are on our own camps are usually better "pimped up" - when we have time :-)
Hope that helps (some ppl may disagree but that's how I see it)