The full tower gives you more options for adding fans to have better air flow. A mid tower can be more cramped inside and wires can be harder to keep out of the way and may prevent good air flow. You don't need to overclock or have water cooling to get a full tower , the added space inside makes it easier to work inside and if you do end up adding anything to the inside you have room for it.
The full tower looks like it has a lot of added ports on the outside top and front and the cooling solution looks better also.
I would choose the Phantom full tower. However your the one buying it and in the end it's your choice if you want to go over the budget to go with the full tower or stay on budget with the mid tower.