No performance difference, just storage & load times. Base model features 64gb flash memory, other two models feature NVMe SSD (in 256gb/512gb)
Face buttons and D-pad sit outside the dual thumbsticks with large trackpads underneath
THERE'S A DOCK
Not a lot of details on pricing/availability but it will allow peripherals and 4K/60 output
First preorders will ship in December 2021 - currently preorders are being taken for Q2 2022.
40Wh battery but not a lot of details on real-life battery usage. Valve says "a couple hours" for gaming and up to 7-8 hours for less intensive use
Valve has said the Steam Deck will allow 3rd party apps and operating systems to function along with the updated SteamOS