what 3150 ip champs are good?

Well depends.

It really up to you who you want to play mid so I not forcing you to play any of the champions I have name here.

if you want a good assassin but with a weak early - strong late game then Akali is pretty well.

If you want a great assasian that works good in team fights with that ult of hers then get Katarina.

If you want a Noob friendly and decent mid laner that can switch to support if one of ur teammates refuse to do that role then get Lux.

There is also Nidalee that is a decent mid laner and her spears can hurt a lot and can turn into a cougar! You could also play her bruiser top or Support if you like.

Their is others like Leblanc which can get very strong but I think she fall off late game I believe. I haven`t really look up guides about her since I do not own her.

Karthus - I believe is pretty good once you get to learn how to play him and stuff.

Kassadin - I not for sure now since he got rework but he might still be a good pick.

Heimerdinger - is pretty good and when I play him he was quite easy and fun in my opinon.

Anivia - I telling you right now I have only played her once so I not for sure about her but I did fine her fun when I did played her.

Karma - I fine also fun to play and is a decent mid to learn. She can Also go support if you like to go that role with her too.

Mordekaiser - I never played against him much at all. Not much to say here but he can be a nice mid laner so I don't know.

So sorry that this is long but I just naming almost all the 3150 champions that can go mid.

I might had miss some so forgive me.

all the champs are "good", it just depends on how you play. So read their abilities, figure out what things you like a champ to have, and see how close to that ideal champ you can get with your IP.

Akali is my favourite champion in the game. She is easy to learn to play at low levels, but still presents a challenge to become proficient at. Her shroud separates the great Akali players from the new Akali players. She's a hybrid champ, so there are a lot of different ways to build her.

Kennen is a 4800 IP champ, but he is also a lot of fun and really underplayed. He is pretty much ungankable due to his speed boost and immunity to unit collision from his E. He can take out an entire minion wave in less than 1 second with his E-W combo late game, and his ult combined with his stun and zhonya's active can turn a team fight. He is viable as an AP top/mid laner, and can be played as an ADC (although he definitely isn't top tier and can't compete with long range champs like Caitlyn). In my opinion he takes more skill than Akali to learn, but he is equally fun to play.

Can you tell I like my ninjas?