Sith are superior to Jedi in nearly every way if you want to really try to dissect things down...
- In hopes of not falling to the "dark side," the Jedi have cut themselves off from everythign that essentially makes the humans human. According to Jedi philosphy, any type of emotion can be a downfall to the dark side. Love? Fall to the dark side. Anger? Fall to the dark side. Fear? Fall to the dark side (no wonder so many Jedi were killed so easily. Fear is a rational response to danger.)
- As a smaller body of power, the Sith are less corruptible and fairly simplistic whereas the Jedi have a central body from which all decisions are made. Oh, and you have to dick around to get the rank of you wanna get anywhere NEAR Jedi Master. Being a Jedi "Master" is a very discriminant title, given it can be implied that a Knight with a Padawan is, technically, a "Master." A true Jedi Master is actually one of twelve members, or who are part of the Jedi council. That's twelve out of about 125,000 Jedi roughly. (I'm guessing low for the total Jedi count.)
- The Jedi way essentially is to accept that hey, you're living a suicide mission. You will die, there's SHIT you can do about it and then, hey, you might be lucky to live for a while as a Force ghost but then you've gotta go and die. Your story's done, you'll be lucky if you're remembered twenty years after you're dead if you're Jedi. As a Sith, you actually have the option of storing your spirit in a lightsaber crystal, prolonging your time as a Force ghost or otherwise living on in legend. I like the latter, don't you?
- Jedi, once upon a time, actually were allowed to have families and children to not being allowed period. Over the years, the belief mutated into something where any family connections was a thing to be severed, entirely. This meant being taken as a baby, raised essentially knowing you were going to be evermore alone until you died, and so on. The belief was so solely corrupted that a simple emotional attachment can get a Jedi expelled from the Jedi order if they're found out.
In conclusion, the Jedi are over rated when you REALLY want to think about it. I could make more points but then I'd get redundant.