Here is my Dilemma, I have just started playing ranked and am looking for a good midlaner to play in Solo-q or with my friends. I was Looking at Xerth 
, Ekko 
, Viktor 
, or Vlad 
. I have played Vlad and ekko and are pretty good at both. I just wanted your guys input on who to buy, if you have any other suggestions please tell me, thanks!
(I currently play ahri, Leblanc, and Fizz to give you guys an idea.)
If you already play 3 midlaners (all AP mage/assassins, too), it might be a good idea to get a champion for another lane, just in case you don't get your lane. Or maybe get an AD midlaner.
From what you said it looks like you mainly play high-mobility burst champions, so you'd definitely like Ekko. I also suggest Akali, Diana, and Nidalee for AP midlaner. Xerath, Viktor, and Vlad are pretty immobile (Viktor has an AoE slow/stun+MS boost, but it's still not as mobile as dashes), so if you wanna try new things, you could do that. Xerath is a decent support and Vlad is a good top laner too, so you'll have some diversity in your champion pool.
Xerath is weak in the current meta. I personally like viktor because he has good poke range and can deal high burst damage. But the others are good as well. It will come down to your personal preference.
Ekko is bursty and very elusive. His ult and damage is just too good to pass up.
Vlad is more sustain type of champion. His laning phase for me is kind of boring, but if you like go for it
