Fabricators need a mental rework

They allredy have clear uses.

For base building vehicle is best (As in, inside your base so they dont have to travel).
For mex building on the first world bots tend to be best.
For rapid expansion (taking all the mexes) on moons/other worlds air tends to be best.

(I assume the build effectiveness alone is still Vehicle > Bot > Air).

Spending the full 27 isn't "efficient" unless you're actively building both types of Advanced factories. That's the point I was making when I posted that. If you're only going to build Levellers, as was often the case in 58772, you should spend that extra 3 a second so you get the same amount of build power but can plop an advanced vehicle factory down anywhere you like, rather than have to requisition a vehicle fabber from elsewhere. Clearly the whole balance has changed now, so my opinion isn't really worth anything, and I've already negatively contributed to this thread enough. Continue in PM please.

Three guesses? Least amount possible so Ant production could be maximised. The other one who uses the word efficient a lot.

On vehicles and bots

For base building (first factory), bot factories are still cheaper to run, so you spend a smaller proportion of your economy on them.
Bots are also more maneuverable than vehicles (bots have 720 acceleration and 720 turn rate, vehicles 360 and 360, both have same brake rate). So in an "urban" environment where there is lots of turning/accelerating and decelerating, bots are more maneuverable, and will start any project at least half a tick before the vehicle that shared the same start position.
Bots and Vehicles have the same top speed.
Bots and Vehicles both build at 10 metal and 1000 energy

Honestly even now, the only use for the vehicle is to build t2 factories.

Personally I'd make vehicle fabbers amphibious so you can use them to cross lakes and so on. That would differentiate them and be useful to tackle smaller areas of water (where it doesn't make sense to build sea).

I said who, what are you talking about?

Here's my idea of fabber rebalance:

Bots keep basically the same stats they already have.
Vehicles get a bit tougher, and have better energy/mass efficiency.
Air fabbers get a 50% increase in build rate (at the same energy cost, leaving them still behind), and faster acceleration
Naval fabbers get more HP
Advanced fabbers in general get more buildpower for their cost, but slightly worse energy efficiency.

The idea is that each fabber type has certain scenarios where it would be the optimal choice.

Why not just make all fabbers have the same energy efficiency? People are worried about players forming "air fabber blobs", but I don't think this is a problem. Air fabbers die in 1 hit from a T1 fighter and are already quite slow. If your enemy was using this tactic it would be ridiculously easy to snipe his fabbers by tossing a few fighters at his base every now and then. As for bot/vehicle fabbers, just make bots faster/low hp and vehicles slower/more hp (a lot more hp than currently).

Or, if you want to really change things up (and remove a lot of unit bloat), get rid of this notion of "combat fabbers". Remove the current "combat fabber", make the current bot fabber the "combat fabber" and let the vehicle fabber be the "standard fabber". If you want to differentiate them even further, give bots the ability to make defenses/factories/mines (and mexes), but not other econ structures, then let vehicle fabbers build everything else. Now it makes sense to use bots for expansion and defensive structures (hell rename them to sappers even), and the vehicle fabber is remade as the "base fabber" for econ expansion or as a more sturdy (but slower) expansion unit.

I agree with your statement about the Air fabbers, after playing in the tournament, its so easy to set a patrol pattern over an enemy's base and annihilate that specific fabber.

I'm okay with the land and bot fabbers, it just seems unfair for those people with naval starts with disproportionate fabber efficiency costs

for me:
Bot Fabber should be nerfed
Build Rate 10->8
Health 150->100

Vehicle Fabber
Health 100->150

Both Ship fabber, and Air Fabber are good...