They look different! Obviously, if we were to put brackets on lingual surfaces of teeth, instead of usual front side of teeth, they would not be visible to others. Lingual approach is mostly for esthetics, where one does not want to show others that he/she is going through orthodontic treatment. They are both designed to achieve proper alignment of teeth. Should consider invisalign if you are concerned with showing.
Braces. Lingual braces can not be seen but are a little harder to get use to with some people. Front braces will bother your lips while lingual braces will mess with your tongue.
Esthetics, comfort. Lingual braces were developed strictly to appeal to patients for esthetic reasons. Moving teeth with either type of braces still involves wires, elastics, etc. Is is a bit more difficult to work and be worked-on when braces are inside and the tongue may get "beaten-up" a bit more with lingual braces.
One is in front. Lingual braces are braces that are put on the back side of your teeth while normal braces go on the front side. Lingual braces are a relatively new invention and are primarily done for aesthetics of people that dont want to show they have braces (mostly adults). The down side to lingual braces are they cost more and treatment time is often longer, and they can irritate your tongue (vs your cheeks.
Many. Lingual braces invisible. Wire length between brackets shorter with lingual braces than regular braces, extending time in Rx. Lingual braces can adversely affect speech, especially when new. Sometimes regular braces needed for finishing detail. Ask your Orthodontic Specialist what he/she thinks will be best to resolve your unique problem set.