About S-Ranks...

[Omar]

that is why they are good

Not just that though. As you have yet to earn an Srank, I do wonder how you would know about them =/

Srank weapons are great because they can have a custom name, have red writing (!! ), higher ATP than most rare weapons in their class usually and can have a custom special. They are also cool because you feel really uber when using them in public for the first time, as it is something to remind you and others of how you managed to complete Cmode in Srank time.