I ran my tank for 10 yeas without a controller, I think it's a luxury item you should pick up once you've spent all your good money on things you really need
It's nice to have access to my pumps and lighting, etc, from my phone, and it's great in that it runs my lighting and pump profiles, but really not a "must have" item. If you've got an extra $500, sure, they're nice, but that's a lot of livestock you can add.