We have had four days of hello fresh for a couple of years, and found it great for both potion size and variety. Also, when DSD14 joined the household it got her into cooking and she had a go at prepping most evening meals with me.
However. We were given three weeks worth of simply cook boxes last month - they've been great. You only get three little pots of rub/stock/seasoning, and have to buy the fresh produce yourself, but they go through the letterbox and are a MILLION times easier to prepare.
Our main issue with hello fresh was always having to be in to receive the box (varied working hours, so not always at home) so letterbox is easier from that respect. I do a supermarket run every week anyway to do lunches/breakfasts/other meals etc, so picking up the bits you need is no hardship, all ingredients are clearly listed, so you have a simple, lazy shopping list. Financially they seem a better bet too.
Didn't think we would budge from hello fresh, but think we have been converted.
Handy not to have to get rid of the frigging massive box too... although the dogs are disappointed, it was their favourite weekly toy.