Using a MOSFET should be fine, you need to make sure you keep the MOSFET within its safe-operating-area during turn-on/off.
You could also consider using a USB power switch, such as the Texas Instruments TPS2051B. USB power switches have soft-start control, over-current output indicator, and they keep their internal MOSFET within its safe-operating-area.
USB power switches are useful for power-sequencing without having to use separate linear regulators. Though I would recommend comparing the price on the MOSFET vs switch vs linear regulator.
Cheers,
Dave