I had my in-laws buy this last time around for our giant almost 3 year old (35 pounds, 40" tall) for their car. It's great for them to have because it's extremely light, folds up when not in use, and therefore can be taken out or put in with ease by anyone.
It uses the car's built in seat belts, so that was a "treat" for her to not be strapped in with a 5 point harness system.
I'm not sure if I'd personally use this 24/7 (undecided on that at this point) but it's a great for us to have as backup and as an extra one for the family who visits once a week with their car.
Also have to add that we got the green one, and it's a lime green, not a yellow green. I like the color.