It's not a debate for what's better; instead, it's the concern of your safety.
The regulatory authority for protective equipment OSHA has standardized composite toe and steel toe for welding work boots.
Keeping in view the specifications of both types of toe caps, we can't conclude which one is better.
But you can choose from steel toe and composite toe based on the nature of your job.
The composite-toe welding work boots can be given preference over steel-toe welding work boots in some cases.
If you are working in a secure zone and require to go through metal detectors, you should prefer composite-toe welding work boots.
Or, if you are working in a cold environment, you should also prefer composite toe welding work boots because of their insulating property.
Otherwise, steel-toe welding work boots are a great option.