I purchased both for my two toddlers, and have used them extensively for numerous car trips in a wide range of vehicles.Price/Value: TieBoth are priced around $35-40, and each contains a seat, carry bag and manual. Both have lifetime satisfaction guarantees.Materials and Build: hiccapopBoth booster seats use a drawstring bag for storage, with a spring-loaded cord lock. I prefer the smaller, stretchy fabric BubbleBum bag, whereas the hiccapop bag is unnecessarily large, but is made of a water-resistant nylon which will probably last longer. Both seats have nice fabric covers that are well made, and seem durable, and come in a few color options. The hiccapop’s cover is removable (with a zipper) and is machine washable, whereas the BubbleBum is surface clean only and should not be removed (according to the manual). The BubbleBum advertises as having a safety and stability system built in, which consists of memory foam and padding over the air chamber, with a reinforced harness around the cover. Apparently this stabilizes movement and keeps its structural integrity, and there is probably some validity to those claims. The hiccapop is just an air bladder inside the cover. That said, the hiccapop’s underside is flat, with a non-skid fabric (more on that later) whereas the BubbleBum’s is a smooth fabric which also has a lot of straps that make it harder to place perfectly flat on a seat. For the seatbelt clips, the BubbleBum uses toughened polymer (plastic), and hiccapop uses coated metal for the lap belt and polymer for the shoulder belt (incidentally, BubbleBum says metal can bend, and hiccapop implies that plastic is not as durable). I don’t think it makes much of a difference safety-wise, but I slightly prefer the metal on the hiccapop (which is used for car seatbelts, even when covered in plastic), even if it adds a bit more weight (1.3lbs vs. <1lb).Ease of Setup and Installation: TieBoth booster seats have an inflation valve to inflate to size. The BubbleBum has an external screw valve at the back of the seat. It’s very easy and intuitive to open and close, and to wrap your lips around when inflating. But it’s hard to retain the air when closing the valve after inflation. Also, the valve protrudes from the seat, which can be more uncomfortable for the child if shifting around, and can leave a temporary mark on the upholstery. The hiccapop has a flat valve with a flap under the fabric cover at the front. It’s more fiddly to open and close the flap, and a bit more cumbersome to put your mouth around to inflate. It still inflates quickly, and holds the air in while taking a breath, however it does require that you need to stick your finger into the valve to get all the air out when deflating. Being under the cover means it’s more protected, but you have to open and close the zipper.To install, both seats are placed directly on the car seat. With the child then sitting on the seat, the seatbelt comes across the child’s lap, and is clipped into the belt loops on each side of the booster. Then the positioning clip attaches to the shoulder belt behind the child’s shoulder. On the BubbleBum, the shoulder belt positioning clip can slide from one side of the seat to the other along a strap underneath, which is helpful when installing or moving in a new vehicle, especially rideshares and taxis. But the clip is just a plastic loop that I found to slide around on the belt, and can sometimes slide off a fidgety kid’s shoulder. On the hiccapop, you have to attach the shoulder belt positioning clip on a loop on the left or right side of the seat, which takes a bit more time if you have to change seats. But the clip actually snaps closed and secures firmly onto the shoulder belt, keeping it in place.Uninstalling is to do the reverse, and is quick and easy for both. Also, both designs allow you to slip the user manual inside the cover for storage on the go.Comfort: hiccapopThe hiccapop seat is about 20% larger, and has side bolsters which provide more support. With the extra size, this is equivalent to the additional weight and volume of a medium-sized apple, which may be important for some. The BubbleBum has memory foam and padding, but from a comfort standpoint, it doesn’t feel appreciably better, at least according to my kids who have used them extensively. Also, the hiccapop has a grippy texture on the bottom which prevents it from sliding around. For slightly longer trips, this is important to stop it from moving out of position and becoming uncomfortable to sit on. The hiccapop advertises this as an important feature (twice, in fact), and until I saw it in action I didn’t fully appreciate how important it was.Safety: TieBoth meet or exceed federal standards for car seat safety. The BubbleBum advertises as also meeting rollover standards, but I believe this is more a matter of actually having the test done, rather than not potentially applying to other booster seats. After all, most seats are similarly minimal in design. But it does give peace of mind knowing it was tested. As indicated above, the BubbleBum has padding and reinforcements for safety and stability, but that’s only as good as the when the seat stays in place. The fact that the hiccapop stays in place more easily, and secures better at the shoulder, gives me more assurance that it will be used as designed.Conclusion: hiccapopTo be honest, I like both seats and will continue to use them. Both are safe and fairly easy to use. Unfortunately the BubbleBum’s smaller size, non-washable cover with the slippery underside material, and poor shoulder belt positioning clip make it less useful for us. That said, it is more compact, and has more emphasis placed on the safety of its materials (but whether or not those features actually make a difference in a crash is debatable since both booster seats pass safety standards).