Predictability goes both ways. One can ready a Z move expecting a switch out, or use a Z move and get switched out on. It's basically like putting almost all your eggs in one big basket, so it's meant to be risky. There are safer, more viable options in Z moves that can buff Pokémon that sorely need it. The same goes for Megas, offensive ones are usually risky (Alakazam, Blaziken, Beedrill, Lucario) once a battle, but there are safer, more viable Megas that are more likely to win (Slowbro, Salamence, Sableye, Venusaur, Tyranitar), and it buffs many Pokémon that sorely need a buff. In conclusion they're both shark jumping ideas (thanks
>>31212422) but since Megas have an aesthetic change I'd say Megas are better.
