At 4.29% I think that is going to work out over a long time horizon for 10+ years. You've got a real borrowing cost of 1-2.5% so you need to make that post-tax on your investments to come ahead. Contrary to what's been said here I would invest that abroad where the expected returns right now are a bit higher. A mix of USA, Europe and Emerging Markets would be my choice but do your own due diligence.
Apart from a few long tail risks (think deflations, political confiscation, broker fraud, changes to tax law), your major risk is liquidity. Will you always be able to pay those interest payments? I'll probably be seen as a bit old fashioned in saying this but dividends will lower your liquidity risk.
When does your debts interest kick in and is it linked to you having a job at all? If you only start paying them back once you get a job then I would be very tempted to borrow all I could get. This is what I did in my home country (the UK), where you only pay back student loans once you pass a certain threshold. Worked out very well in 2008-2010 when I did it but then again I did get very lucky. That is a reason why I'm optimistic this kind of strategy (so take such optimism into account!)