I think that scar removing silicone sheets and scar creams are the best. There are no side effects and they work for most scars. Of course it requires consistent use and patience because it can take a long time but it's worth it.
The only exception are keloid scars which are very hard to get rid of. If anyone here is considering surgery for a keloid scar, don't do it. My brother had a keloid scar removed and guess what, another keloid scar formed as a result.