Having experienced all three, by working as a grad student, as well as in a quant fund and starting an internet/tech startup, I can say that I gained enjoyment from all of these roles.
Each experience presented interesting challenges. Quant trading was very mathematical, academically interesting and presented "big data" issues right at the start. Tech startups taught me a lot about management, getting things done (TM) and why you need to have a market BEFORE building a product! Academia taught me how to really analyse a problem to an extreme degree and how to quickly find solutions.
Right now I'm enjoying building quant trading systems. To a certain extent they can be fully automated (although you have to be aware of "alpha decay" - i.e. strategies losing their profitability over time) and thus it is possible to have other interests.
Each experience presented interesting challenges. Quant trading was very mathematical, academically interesting and presented "big data" issues right at the start. Tech startups taught me a lot about management, getting things done (TM) and why you need to have a market BEFORE building a product! Academia taught me how to really analyse a problem to an extreme degree and how to quickly find solutions.
Right now I'm enjoying building quant trading systems. To a certain extent they can be fully automated (although you have to be aware of "alpha decay" - i.e. strategies losing their profitability over time) and thus it is possible to have other interests.