It depends on what's available to you locally, as well as the condition of your over all health. My HRT is under the care of a Family Medicine doctor who has experience with trans patients.
If you have a relationship with a general/family practice doctor already, you may want to start there, as this will be somebody who knows you and your family medical history.
But I certainly wouldn't expect anyone to argue against an endocrinologist, either, at least for periodic evaluation.