Both work; it’s a trade-off.
Wire floor (½" mesh or so): droppings fall through, so it stays cleaner and drier with less daily work. Downside: can be hard on feet over time. Use small enough mesh that feet can’t fall through, and give them a solid board or resting spot to get off the wire.
Solid floor with bedding (pine shavings, hemp, sand): more natural, lets them dust-bathe and scratch, easier on feet. Downside: needs cleaning more often to stay dry — damp bedding is where ammonia and illness start.
Whatever you choose, the real enemy is moisture. A dry cage with good airflow beats the “perfect” flooring every time. What are you running, and how often do you clean?