We have stayed at all levels. I personally prefer the deluxes, but the grandkids prefer Pop Century and so to make them happy, that is where we will stay until they all outgrow it. I have 7 grandkids under 9, so that will be a while, I'm afraid...it is not a matter of economics for us, but a desire to make the experience as fun as we can for the kids. If I happen to go without kids, I will stay deluxe. The point is, while I love deluxe, Pop is quite a lot of fun too. We will stay wherever the kids want to stay. I will just have to pack a coffee pot.
Your grandkids are lucky to have you.
My children actually don't care where we stay as long as there's a pool. So luckily all Disney resort has at least one pool! It is nice to put moderate or deluxe in the mix sometimes.

It's just a matter of personal preference. There are some deluxes that I'd actually choose a value over. I didn't enjoy our stay at SSR, so I'd choose a value over going back there. And the GF does nothing for me with its "grandma's cottage" rooms, so I'd much more happily accept a mod or value over it. More expensive does not automatically="better" for all people.