We are paying up front. Partly because we can, but also because we are concerned that DC should have the chance of staying in their home town and work in rewarding careers of their choosing, and have a decent life.
Debt is debt. London was always expensive and at times we have really struggled with mortgage and school fees. The latter as a result of a similar calculation about whether to pay schools fees, pay railfare, or pay additional mortgage to live in an area with better schools. (The decider was that living near work gave DH more time with our children even if it meant living in a bit of an educational black hole, and me working full time.) It is only now, with our mortgage paid off and school fees coming to an end, that we are finally getting our heads above the water. Repaying student loan on top would have been too much.
Leaving University with a clean slate will mean DC will feel more able to apply for jobs that interest them, whether teacher, health worker or civil servant. If they stay in London, they will still struggle to afford accomodation, so they won't get an easy ride even with loan repayments. Then having this choice will give us more satisfaction that seeing them take City jobs just for the money, whilst we spend our newly available cash on cars or holidays.
I know the money saving tip is to do clever things with savings accounts. But I think the life lesson is more than just considering the technical elements. Not getting into debt unless you have to, and when you do, eg a mortgage, consider the implications carefully, is also a good approach. It means that when the unexpected happens you have flexibility, which is worth a lot as well. One example perhaps. Three or four years into a professional career and a DC is offered a three year secondment to the London office, which will vastly increase long-term promotion prospects. One turns it down because with loan repayments, living in London is simply unaffordable. The other recofgnises that it will involve belt-tightening, but is able to say yes.