Fizz is my main. I will never go back. I honestly don't like to play really any other champ over him because he is just so fun. The mobility, the Trickery, the Troll Pole, The Ult. So much finesse, and so much damage.
It's just a shame though that his 3 of 4 of his moves are bugged, and I don't see any fixes coming soon. While playing him I have (painfully) dealt with these major bugs that can break a fight for a Fizz;
Q: When Fizz Urchin Strikes an enemy champ, if they charge, it prevents all incoming damage from Fizz. While it is of course fair that their charge should deal damage to Fizz, as it does, to omit what could be a killing blow and an escape for Fizz now becomes a wasted move, and often a death.
E: Hard to explain exactly how this works, but when it is a well-known and glaringly obvious bug. Basically, sometimes when you land back down from your CC Immunity, you land and 'stun' yourself, making it unable to move for a second. Whut.... Also, any damage that he would do to a nearby champ is now omitted.
A more common bug with E is really just a matter of cleaning up the maps. All too often, I try to E over a corner of a map, only to find my face smashing into an invisible wall. Turns out, all LoL maps are littered with these un-cropped, unpolished walls that hover over the corner of a wall or obstacle. Playing Fizz, you often need to gain distance as quickly as possible from your pursuers, so you try to jump over a wall immediately. A lot of the time, the closest part of the wall is the corner. I have now learned not to hop most corners, and it leads to a failed escape.
R: Straightforward bug (literally). Once in a while, Fizz's Chum the Waters passes directly through an enemy champion. Feel free to tell me it's because of a missed shot, the shark needs to hit the champion directly, but it has indeed happened more than once. The shark can literally pass directly through the body of a champion and go beyond him/her. I would say a simple and small hotbox enlargement could fix this glitch entirely.
All in all, these glitches are so easy to patch, we just need Riot to see them, acknowledge them, and act upon them. With a champ as reliant on each spell-cast as Fizz, any one of these bugs can ruin a fight, escape, or game.