Topspin Gordo takes years to start up and is still reflected for free. Bouncing Gordo lingers on the field for a good while, but is much less rewarding on hit and, again, can turn into being your opponent's lingering projectile pretty easily. On the other hand, Dedede can also throw it much higher/farther than the other Gordos, so it can actually be used to combat projectile camping or to punish opponents recovering high. Bouncing can do some fun stuff, but default's generally the best for both reward and versatility.
All downB variants are booty. Default has the most kill power by a substantial margin, Armored isn't actually a usable anti-juggle tool because its super armor only functions grounded iirc, Dash is weak and air versions of all Jet Hammers are weaker, so even its niche as a sort of air dash attack is dubious at best.
I don't have much of an opinion on his other customs, Rising Dedede is cool but I like it less after 1.0.4 ruined its combo potential with dthrow (used to be a kill combo, dthrow's new trajectory either results in the weak hit or nothing at all). Dedede doesn't really get "better" moves from customs, just more options.