Hi,
both will do the job, but I'd say ( even though I am affiliated to Photon) Photon is easier, more robust, battle tested and cheaper.
so this is your first Multiplayer game go for Photon, it's already quite a stretch to understand all the concepts, but if you put unet in the mix, this is definitly for advanced users with lots of experience and clear project with proper budget for production and monthly costs.
Bye,
Jean