I think its a bit of a mixed bag.  One of my buddies prefers to play against the computer when we get together.  We typically play 2 v 3 hard + 1 normal and win 100% of the time.  We played last night and actually lost even with me being pretty OP early on (map was crucible).  So, it looks likes it a little better.  I played a 1v1 hard ai game and saw the ai come in and crap one my portals near base very quickly, so I had to address that (map = cataract).  That's the good stuff, imo. 

The bad stuff - I find the AI will often make crazy decisions when by itself.  This was most noticiable on crucible to me.  During conquest games, if I'm beating on the ai in the middle of the map, it often runs off, away from its defences towards the gold mine/artifact flag.  Obviously not the smartest move, especially in a 1v1 scenario.  I'm guessing this is just a bug as the ai does try to flee... generally speaking, though, I haven't seen anything all that great, but I am very happy that improvements are being made. 

Has the AI really been improved? Everytime an update comes down, I read through all the changes in it and I hadn't noticed any mention of AI improvements. I played Tournament on Hard and won, but still lost a couple of games due to the incredibly awful behaviour of my AI team mates. I noticed an Oak just standing around near a flag we already captured for nearly a minute, not moving at all. There was an enemy Regulus hovering near him that didn't appear to be doing anything either. I don't know what all that was about. Meanwhile in a Conquest game on The Brothers, my team mates did a fantastic job of feeding the enemy for a while before finally buggering off to piss around on the far right whilst the other enemy DGs who were well-levelled by this point and had catapults, got the opposite portal and ploughed right through the left flank to the citadel, leaving me to repeatedly fight two DGs on my own with no support.

Does anyone know what changes have actually been made to the AI (assuming there were)?

EDIT: I'm talking absolute CRAP and everyone should ignore me. There's a list of the AI adjustments in the changes list. To redeem myself, here they are:

1. Adjustments to caution and hazard detection and avoidance.
2. Adjusted health level flee percentage.
3. Demigods do not use minions when fleeing, may summon minions in combat.
4. Improved teleportation
5. Increased Demigod planning frequency
6. Improved item usage when endangered.
7. Tower tag improved.

The AI is still way to aggressive for UB, he is trash. Gets sniped all the time trying to run with 100 hp.

I'm going to retract my earlier statement even further. It still does stupid things, but I've just played a couple of tournament games and I think it's definitely playing better. At least the enemy AI is, not convinced my team mates are any better, but then it was on hard so they're supposed to be weaker, I guess.

There needs to be a better way of making "Hard" and "Nightmare" tougher than making your team mates more likely to lose you the game, though.

It still has problems with learning when to retreat.  While the AI does run when it detects 2+ Demigods targetting him, his retreat usually consists of walking only a few yards out of view.  With usually only 500-750 health left, a ranged ability usually takes him out.  I also don't see the AI using towers as protection alot of the time.  Once the AI gets behind in levels, it doesn't play conservatively at all....focusing on trying to kill a Demigod with a 5+ level difference instead of farming for grunts.

In other words....you have to run for your easy kills now instead of the AI walking in front of you, passing 4 towers in the process

Was playing a 4vs4 game with 1 AI on our side.  He went 0-16

There is one UB AI that is completely worthless. He will do one of the following

1) sits behind the towers for minutes at a time.

2) Doesn't cap the flags all the way. Just to nuetral

3) Is an ooze build that doesn't buy regen gear. Runs all the way back to cit with ooze on (Reg got soo many sniper kills on him it was ridiculous.

I have also experienced the UB being absolutely useless although it wasn't an ooze UB, it was a spit UB. 

Pantheon game, double Oak vs double beast, each team had 1 AI.  The AI beast was absolutely-fucking-terrible.  It spent all its gold on the most useless possible citadel upgrades EG; building damage, respawn timer, priests.  I don't think it bought ANY items because at level 8 it barely had more than 2k HP, by contrast even the AI oak had 3k+.  Even though it had put  points in spit, 99% of the time it would simply auto-attack until it hit 1k HP at which point it would retreat/hide behind towers.  Since it only had 2k max HP, it could only engage for 5 second before running away.

I also agree with Busdude... for me, if I'm playing with reasonably matched opponents and I get stuck with an AI on my team due to dropping, I'm more than likely going to lose.  BUT - I think they play better in direct human v ai games.  So, while that is nice, it would be great if I wasn't forced to conclude I will lose if I get an AI teammate against decents opponents.

Regarding the purchase of inappropriate items, I'm guessing that this is semi-random. Wouldn't it be better if, even though it's less dynamic, the devs wrote out some prepared build paths for different DGs. So for example, UB would have a dozen set build paths, some ooze, some spit, etc. Spit ones might have a selection list of appropriate items when they had the money that included a mana-regen item, the ooze build would not have any mana-regen in its selection list. Okay - it's not full AI, but with a dozen different build paths for each DG (which wouldn't take long to configure) nobody would know or care that patterns repeated. And even then, you could have some randomness depending on how much gold it has or which path its already started down. It would just eliminate some of the sillier cases.