You may have heard it is better to nail a floor than to staple it. The jury is still out on this, and there is some debate, but it seems to boil down to a personal preference. In the right application, both methods will serve you well. If either method appeals to you, or if you have easier access to one type of nailer over another, then choose accordingly.
But there are a few situations where one fastener makes more sense than the other.
If the floor is a thinner material, staples are your only answer. Engineered flooring does not have as much wood to shoot through, and that means there is less wood to hold the nail in place. For this, a crown staple is the only workable solution.
Solid 3/4" flooring can be fastened with cleat nails. This is a specialized flooring fastener with an angled cleat at the top so that it doesn't pull through the flooring and a barbed shank that won't pull out of the subfloor. The Stanley Bostich Manual Cleat Nailer MFN200 is a fully manual tool that requires no compressor or hose and which is activated by striking the tool with a rubber mallet. More effort, but no compressor. That appeals to many.
Finish nailers are useful for starter rows. As you begin your flooring project, you will need to nail down the first row next to the wall. You may also need to angle a finish nail into the tongue to start your project, because the flooring nailer needs room to set and usually can't nail that close.
There is another nailing option called face nailing. This is a look that matches old homes with plank floors. A plank floor is simply wider boards milled with square edges. An internet search for face nailed floors will turn up all sorts of ideas and advice on this.
Stanley also makes pneumatic, or air assisted flooring nailers, as does Portamatic. An Internet search using the terms flooring nailers or cleat nailers will bring you results reflecting a long list of options. When choosing nails for your floor, choose a length that allows for at least 1" of bite into the subfloor. Considering that the nail goes in at a sharp angle, that means a 2" nail for a 3/4" flooring or at least 1 1/2" for a 1/2" board.