I'll give both a try but just from looks Teamfight Tactics looks kinda a bit more boring.
Riot Games Launching Teamfight Tactics in League of Legends to challenge DOTA Underlords by Valve
How do you know when your game will be the next big thing? When not one but two developers are ripping you off!
Hot on the heels of Valve's DOTA Underlords, Riot Games has just announced Teamfight Tactics in League of Legends! Teamfight Tactics mode will be available on LoL PBE on June 18 and will probably go live officially in patch 9.13.
Like Valve, Riot developers aren't shy about ripping off Autochess for their own game,
folks around the office have been playing an insane amount of Dota Auto Chess in particular. We love it, and it actually got us inspired to create something new as a mode in League.
The introduction of Teamfight Tactics will also bring a whole new personalization option to LoL: Little Legends. These critters will be your avatar in TFT, dancing, emoting, animating, and generally showing off.
Teamfight Tactics will allow players to recruit recognisable League champions to the team by spending gold between rounds and combine duplicates to get more powerful units. Sit back and watch selected units do battle against teams positioned by other players.
Yep, that pretty much sounds exactly like DOTA Autochess. Now Riot and Valve can duke it out just like Autochess too.
The new BR in game industry.
When will blizzard make their move? Hm
(ctrl C + ctrl V) Now i have done my homework :)