Between Diamond Tiara taking the lead and operating solo sometimes, and some other clues, there's room for doubt. But then, we know so much less about Silver's family and situation than Diamond's - so instead of just arguing who's worst, feel free to talk about those two more generally.

Not really - just as Spoiled Rich is a bad influence on her daughter, so said daughter becomes a bad influence on her friend. Not that Silver's a particularly nice pony, but on her own she wouldn't be nearly as much of a bully for a few reasons:

• She's less proactive - more likely to laugh about you behind your back, or even just look down on you in her head, than insult you to your face unless you do something to her first - or she's trying to impress Diamond.
• She's a lot more willing to acknowledge other ponies' good points when she actually recognises them - partly because she feels more secure in her own status than DT.
• She's nicer to her family servants than Diamond is to poor Randolph - although that's probably because her parents wouldn't stand for it any other way. In fact a lot of Silver's better points can be traced back to her having a more all-round supportive home life than DT.

31. Is Silver Spoon equally as bad as Diamond Tiara?
Silver Spoon is just as bad as Diamond Tiara morally. Although Silver seems to be more follower than leader so she's less harmful when alone.

I know a lot of people get upset at the idea Silver Spoon was just a follower, but I can't see it any other way. Maybe she's softer-hearted, maybe she isn't, but Diamond was always going to be worse, and her will was always going to override Silver's.

Not that it matters, since neither of them exists anymore.

7038980
You have a very "now" view of Equestria, don't you? You might fit in well in the fashion world, where things are either new or dead.

7030401 Silver Spoon always seemed to be more of a lackey or follower to Diamond Tiara. She was the first to applaud Granny Smith's story in "Family Appreciation Day", and she clearly resented Diamond ignoring her advice in "Crusaders of the Lost Mark". I just wish Hasbro hadn't shot down all the ideas pitched about Diamond Tiara post reformation, I bet one of them involved patching things up with Silver Spoon.

7039032
They patched things up in the episode. But I do expect they would probably both have appeared together. Hmm... perhaps an episode where DT is now making more friends, and SS is kind of worried/jealous? They sort of did that with Discord, of course, but still...

Believe it or not, both of these girls think that they are helping every other pony grow, by pushing them to better themselves. This is one of the problems in children: they emulate what their parents do even when they don't understand. Silver Spoon follows Diamond Tiara because she seems more confident in her actions and Diamond Tiara is so confident that she is doing the right thing because Silver Spoon, her closest friend, hasn't opposed her.... Kids...

7039477 Let's not forget that Diamond was basically pressured a lot by her mom (and perhaps her dad) to uphold the family legacy. And her mom was a very bad influence, molding Diamond to act exactly the same way she did. Whether Silver knew about this is a question in and of itself.