Firefly makes multiple excellent products for children who struggle with mobility or seating. For some children, the GoTo seat has been a great fit. For our little one, it doesn't work in all situations because of her low trunk control and head support.
We have the size 2. If the seat our daughter is in can recline, it works well. For example, we have used it on our porch swing, which has a slanted back, and in her stroller, which also is somewhat reclined. In those situations, the GoTo seat works pretty well. If attached to a regular chair, such as at a restaurant, it does not work as well because it does not provide the head support she needs. We found it will work in a pinch, but we often spend most of our meal repositioning her. However, if space is an issue and there isn't room for her chair, we still use it. With the price of this item ($299) I wish people could try it before buying to see if it will work for their little one.