I keep learning new champs and can dominate in any norm game w/ them. Get into ranked and get shit on, i get mastery with the champs I try and play. Everyone who I play with tell me that i havent found "my champion" any suggestions on who to try and play. I play top lane.
Depends what your looking for:
If you want to play Tanks: 
If you want to play Fighters: 
If you want to play Damage: 
High health builds are bad on him now. Only get 
now if you're against a very high poke champ that you just have to AFK farm against.
He has no bad match-ups. All of them he can farm safely and easily in.
That said, there are match-ups you have to be careful in, but you can scale into the game into any match-up safely.
You're a ticking time bomb. The enemy team essentially loses if you aren't behind, and if you are, you can still easily carry the game. Even if you're far enough behind to not be a damage threat (Psst, you always are with your CR procs, E, and ult), you make your team compensate that with your ult.
Not only that, but his optimal build includes Armor, MR, and health; all of his defensive options are high damage (on him at least) and are his core items. If you get fed, go ahead and build that deathcap/large rod early! It multiplies your healing, damage, and health!
The trick to Vlad is learning how to play each match-up, but starting them neutral. Test your opponents reactions to Q threat, autos, crimson rush threat, E threat, your movement, etc, but be safe about it. Punish them if they don't react, zone them if they do. Always skirt their threat range while doing so.
Even if you can't interact with them without taking a bad trade, you have CR procs you can trade with them for a net-neutral damage on you, and a huge chunk out of them. You have 4 potions and boots to start. You'll probably outlast them.
If you can't even CR trade without getting chunked too hard, you just afk farm; vlad has perfect farming under turret if done correctly; tap E on the wave and they'll all be at a perfect health range to auto for the last hit after a shot or two from the tower! If one's too far off because of enemy minions or something, that's what you're saving Q for if you're not low on HP! Almost nobody can dive you unless they have ignite and can survive going super deep under your tower for three+ seconds with aggro.
Late game, with that AP build, you end up with pretty high resists for a mage, 700+ AP, and ~4500 health. Take blue late game. Its more effective on you than anyone else due to your scaling, build, and passive.
12/18, taking Strength of the Ages; Double-Edged Sword>Feast, Natural Talent>Vampirism, Bounty Hunter>Oppressor in Ferocity tree. Unyielding>Recovery in Resolve.
As far as Runes, you're going to want 10% CDR in there. With Vlad, you get much more going full scaling AP runes with the exception of scaling HP seals and two scaling CDR quints. However, if you don't feel like investing into the scaling AP quint or marks, the 7.8 magic pen and the flat AP work fine, just not as good on him.
Ghost+Flash in most cases. If the enemy team can't deny you from getting into fights from either mobility or CC, you can grab TP over ghost or flash; use your discretion. In others you might want Ignite (rare; almost never worth what you give up) or Exhaust (really cheesy 'counter' like Xin/J4 lvl 2-3 cheese)
You're going to play safe, and you're going to scale into a monster.
