While most phones today don't offer removable batteries anymore. I would definitely prefer phones with removable batteries. I feel you can get more life out of the phone this way, if a battery dies in a phone with a removable battery, you can purchase a new battery for that phone, slap it into the device and it's working again. Not the case with phones with non-removable batteries however. I do see the logic behind not allowing the battery to be removed though, there is a risk of using a 3rd-party replacement battery for a phone that wasn't made by the phone manufacturer.
I guess, it depends on your stance with using 3rd party batteries and how you feel about certain phone manufacturers and their stance on batteries or how reliable said battery may or may not be.
Each has their pros and cons. I guess the non-replace-able battery phones biggest con is, well, you can't remove the battery
