I too tried a Bumbo seat for my son. The only thing is... these are not designed with all babies in mind. At 5 months my son could sit up on his own. I wanted something to keep him stabilized, so I bought the "Bumbo." To my disappointment, his chubby little thighs did not fit well into the seat. If I left him in it for more than 2-3 minutes, he feet and legs would turn really red, as if the circulation was being cut off. He is now 7 months old and weighs almost 26 pounds. Since he is just starting to crawl, his legs are now way too thick to fit into these little "slots."  He was average size at birth, weighing 7.5 pounds. My recommendation would be to try in the store before you buy.