It really does well.
My kid just turned 4 months. We have the cruiser (Tactical Baby Gear Version) for this and he is finally able to support himself sitting up as long as there are restraint. This worked really well and felt secure. Getting it on is easy. Folding the cruiser with it is no problem. It held my 4 month old really well and wasn’t in any danger of falling over. The only real issue I have, and thus the missing star from getting all five is the additional accessories I have for the cruiser. In particular the folding sleeping mat. This complete closes the gap between the sidewalls and the seat, so securing the mat while this is attached is impossible. It’s not foldable to a small size either as it’s sturdy (which is good), but hard to stow away elsewhere. I guess, I just have to plan carefully which one to bring and anticipate our needs. Luckily, I do have the basket that I can stow the seat there. I really wish I can use this and just plop the folding sleeping mat when my baby wants to take a snooze. But for it’s purpose, it’s definitely a great addition to the cruiser.