What's the power level?
Reliability depends a lot on the design, not only on the device. BJTs might seem more rugged as they don't have such a delicate part as the gate, but there are mosfet devices running for many years without problems, protect and drive propperly and you shouldn't have problems. Mosfets runs at loser temp, as a low rds on one will have way lower losses than a saturated. Bjt.
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