Should one take a 2:1 Bsc or a 2:2 MSci?
It really does depend on what the short- and long-term career objectives are. If someone really has no desire to continue on to a PhD, then it probably doesn't make too much of a difference—they're being hired based on what they can do with the master's, rather than the grade, and only a handful of employers will care about the difference between a 2:1 and 2:2.

On the other hand, if at some point, someone wants to go back to graduate school for further training, a 2:2 master's may not be the most useful credential to have on one's record.