This build is actually the best I've seen, quest that you can stack easily on heroes, AOE Slow and Damage, good survivability, overall the best (but remember, Chen is still weak).

Accumulating Flame will improve your waveclear and when your quest is done it will also reward igniting heroes with armor!
Keg Toss is the go-to, while giving you a bit more damage, you will effectively gain range and a second charge on your CC ability.
Bolder Flavor is the only option, more instant and durable shield.
Wandering Keg is my favorite, but Storm, Earth, Fire is still a very good ultimate, especially if you struggle trying to survive.
A Touch of Honey is obvious at this point, 40% slow on a ranged ability with two charges. If the enemy is heavily focussed on spell damage and engaging your team, Withering Flames is also very good to pick.
Another Round is your final piece, now reducing the cooldown of the next basic ability used after Keg Smash touches a hero, meaning you can W+E two times in about 3 to 4 seconds, this deals a ton of damage, slows everyone, and grants you armor!
Stormstout Secret Recipe is the usual option, although Untapped Potential feels very good. If you took Storm, Earth, Fire, Elemental Conduit is awesome.

This build is very funny to play, however it grants less CC and is overall less versatile, good if you need to dive a single target and the enemy is not good at peeling.

Elusive Brawler is an instant bonus which grants you survivability when diving the enemy, if the enemy doesn't have any auto-attack based Assassin, or they have blinds, you can head into other talents.
Deadly Strike is your pick, you want that kick to do more damage, and you want that kick to be up no matter what!
Bolder Flavor is once more of the party, it synergizes with Deadly Strike as well.
Storm, Earth, Fire is more logical if you dive in like crazy, however a good Wandering Keg can always do the job.
Pressure Point is awesome in this build, you can now focus a target much better.
Flying Leap is the only option at this point, you're all in on that kick!
Elemental Conduit should be your pick, you really need the burst survivability and extra mobility granted during it.