I didn't buy one for my babies. It isn't my thing. I think babies gain better motor development laying on the floor and playing , and rolling, and working those muscles so they can sit on their own. I'd be concerned that the bumbo is proping them up so they aren't needing to use their muscles as much, as when you hold them sitting on your lap, the pressure of your hands changes constantly and they gain more strength in their torso to learn to sit on their own. I guess it is partly parenting style as well, It didnt'really use a lot of seated things. I had a jolly jumper I used occasionally, and a high chair for meals, and a swing I used a lot first few months. Some of teh moms in my moms group had everything imaginable, the entire perimiter of the living room would be full of "things " and the babies would go from one thing to another to another the entire time and hardle spend a minute on the floor. Bumbo chair, jolly jumper, jumper roo, bouncy chair, swing, exersaucer. I'm sure some of those babies sat in a container of some type for hours everyday.