I'm honestly not sure, the attraction of general (MEng) is the interdisciplinary knowledge, & the fact you have more time to experience the different disciplines before deciding what to specify in. However the number of universities doing the course is limited, and many aren't accredited because the first cohort haven't finished.
I'm very interested in nuclear, mostly because the degree is very heavy on the physics aspects & unlike some engineering courses physics is a required A-level rather than preferred. My only worry is that there's very few pathways to take within the course, unlike general. As well as limited universities, Warwick, Birmingham etc.
Basically, any suggestions as to which would be best? doesn't have to be from either nuclear or general x