ive used fallout et tu for my first playthru for fallout and it has made the game alot better playing and fixes all the annoying outdated stuff from the game

so et tu

Fix it if you want to keep the game nearly pure fallout 1. It will just patch the game up a bit and allow you to restore cut content. It'll also install small things like the ability to talk to companions and tell them to move, or allowing them to equip armor.

Et Tu if you want all that and some more amenities from F2. Such as a vehicle for faster map travel. Bunch of F2 weapons, the ability to just shove people around.

Fallout Et Tu.

I've played through with both Fixt and Et Tu, but I prefer to use Fallout Et Tu because some of the easier to use exploits like using your NPC as a mega mule that holds everything isn't available, and charisma is calculated by for how many companions you can recruit by default(start with atleast 2 if you want to pick up Ian or Tycho before grabbing dogmeat to die harshly eventually).

Et Tu is also still receiving updates and i'm sure contains hundreds of more fixes and corrections than Fixt or 1.3.5 patch.

There is also a ton of configuration options in Et Tu so that you can tweak the gameplay to your liking.