I think you should pay off the student loans first. But here's a more detailed way to think about it.

I can think of 3 big factors in making a decision like this: 1) your comfort level with debt payments, 2) cash flow, and 3) a financial analysis of the costs and benefits of each approach.

First, your comfort level. How would you feel about your life and your job if you had another required payment each month? Would it be too stressful, or would it not matter?

Second, cash flow. A 30-year mortgage on a $300k loan at 5% is $1,610.46. You can plug whatever numbers you think are appropriate into Excel, but that's more than half your current income. I suspect it would be very tough to find something for much less in Brooklyn. I assume your rent is rolled into your current cost of living of $1300, which mean you pay almost nothing for Brooklyn. Good job! I think you'll have a hard time making that cash flow work, and an impossible time if you still have student loans. What's the rush?

Third, financial analysis. It's hard to do without more information, but basically you can build a spreadsheet that tells you exactly what is going to be financially optimal. You know your student loan interest rate. You know that you get a tax deduction for the interest you're currently paying, so you can calculate exactly what the loan is costing you each year and how that will change over time as you pay less interest and more principal. You can do the same analysis for saving for a down payment, fees, and then mortgage on a property. Can you earn interest in excess of what you're paying on your student loans while you save? Don't forget the taxes on the growth of your savings. In general I think this kind of analysis will show that it's better to pay off loans first, then save for a house. However, there's one case where it might change: are your parents going to help you with a down payment? If you are very close to having enough money for a down payment on a property you can afford right now, you may find that the equation changes. However, given the rough outline you provided about your situation, I think that is highly unlikely.

Anyway, Mustachianism is all about financial freedom and independence, and it seems like piling on more debt wouldn't feel very free. You can't eat your house, and you can't get out of paying your student loans, so it would be a tough situation to be in if anything went wrong. You have a ton of savings already given how much debt you have. I'd suggest you focus hard on your student loans. Don't cut back on the 401k, though--the upside on the tax benefit plus the employer match is huge, as much 70% or more on that first 6% with a 50% employer match. That's way more than a -6.55% interest rate (which is probably more like -4.5% after tax benefits are incorporated.)