We stayed here for a week in February, and I wish we could have stayed longer. The view from the terrace never got old, particularly watching the sunset over the ocean every evening.
Foz is definitely not central Porto, but it's also not too far from the center, we were able to take cheap Uber rides anywhere in Porto we needed to go.
The apartment isn't huge but it makes good use of the available space and was quite comfortable for us (a couple with no kids). Note that one of the bedrooms is a loft space accessed by a ladder, and the other is down a spiral staircase, so I'd avoid this place if you have mobility issues that make climbing stairs or ladders difficult or dangerous for you.
The space was quiet the entire time we were there, and had everything we needed for a comfortable stay. There's a Pingo Doce grocery store a block away and an organic grocery store a block further, we never lacked for food options.
I hope we can come back here some day. Recommended!