The main difference between TF2C's high poly models and SFM models is that TF2C's models are much more detailed then SFM's models and TF2C's hand textures were made to look more detailed then the SFM ones.
Includes cosmetic and workshop taunt compatibility
(Note: clips with more cosmetics then the SFM playermodels mod due to it being higher poly)
Supports ragdoll mods
Semi-Support with texture reskins
And no, it doesn't work in casual (like with most mods)
Short circuit won't disable the hand bodygroup (can't fix for some reason)
Hot hand has the same issue but is already present in live TF2 (just install this mod so there's no clipping)
Decapitation models don't work properly on normal deaths (besides scout for some reason), only special death animations will make these work.
(If anyone knows how to fix either of these, please tell me)
Drop the VPK into the custom folder or create one if you don't have one by going to C:\Program Files (x86)\Steam\steamapps\common\Team Fortress 2\tf\custom and create a folder named "custom"