Velcro can be your enemy in hot and humid climates. People using it on their armor at Disney found that out the hard way as things just kept falling off. It is a great secondary attachment method, but I'd consider having a back-up in place as well.
Personally, the majority of my armor is attached with snaps. If you don't position them too tightly (i.e. bend your arm and a shoulder bell goes POP!), you shouldn't have any problems with them. My knees are held on with elastic straps and velcro sewn to the jumpsuit (perfect for keeping them from slipping down from walking).
