Different isn’t always bad. In this case, it’s all preference. Banded or pneumatic, it’s all up to the spearo’s call.
Are you a high-tech, meticulous type? Do you enjoy maintaining and polishing all of your toys, and putting them on display when they aren’t being used? If so, then the pneumatic style speargun is your go-to. Pneumatic spearguns use air to propel the spear towards your aquatic target. Though this style does possess a boat-ton of power for its size, it is also considered to be a high-maintenance piece, and known to lose power as you descend to deeper depths.