for basic purpose this would be more than enough. but if you can get the 2/4GB model, get that. pi has a lot of use cases apart from pi-hole. and after a while, you would realize that you need more performance. you can use it for torrenting, nas and so much more. for pi-hole alone, you can probably get one of the older model and save money.
Thanks for your reply mate. But hard disk and torrenting is fantastically done by my Asus router. Their firmware is absolutely amazing.