Type of metal, ?
Gauge of metal, ?
Hardened, cold rolled, hot rolled, stainless?
Straight cut, gently curved cut, intricately curved cut, ?
Is the metal flat, slightly not flat, very not flat, ?
Hot clean does the edge need to be?
Are sparks an issue?
Is dust an issue?
Are little chips of metal an issue?
Preferred cost?
There are tons of way to cut metal.
Single and double cut shears from manufacturers like Fein, Trumpf, Draco, Kett, etc. are pleasant to use but can be expensive.
Kett is probably the most affordable.
If you don’t mind spending the extra money, it’s probably best to purchase the 14gauge version, since it will allow you to cut heavier gauge metal in future if necessary.
Nibblers are great for complex shapes, but the chunks of metal they shoot out destroy shoe and boot soles.
The cheap nibbler attachments seem to work, but I don’t know how great they are for extensive work.
A decent jigsaw with metal blades can cut metal quickly, and fairly cheaply, and is versatile for other stuff.