I often see the websites using font \"Helvetica Neue\". Is this font safe to use, like eg. Arial? Or do the browsers have trouble rendering it or not many machines have this fon
Most windows users won't have that font on their computers. Also, you can't just submit it to your server and call it using font-face because this isn't a free font...
And last, but not least, answering the question that nobody mentioned yet, Helvetica and Helvetica Neue do not render well on screen unless they have a really big font-size
. You'll find a lot of pages using this font, and in all of them you'll see that the top border of a line of text looks wavy and that some letters look taller than others. In my opinion this is the main reason why you shouldn't use it. There are other options for you to use, like Open Sans.