It depends a lot on the players involved. I've seen powerful, dedicated A/Ts and weak A/Ts. Bizarrely the weakness is often more Austria being paranoid than Turkey being greedy. Even if the Turk does intend to stab, it normally comes after the invasion of Italy and Russia, by which point a suitably forceful Austria can have quite a few units, and with any luck the Western powers will make the stab inviable. However, if Turkey is greedy or Austria paranoid, it is a very instable alliance indeed, and probably won't be successful.

I've seen working alliances, too. I think the main problem is that the best route for Turkey's units to take to the front passes by Austrian SCs most of the time, leading to suspicion and fear. For me, the number one way to build alliance-trust is to never have to bring your units near their SCs.

AT is a very useful alliance, but will tend to struggle against EF.
Becomes much more useful in gunboat, when it seems to be almost the only chance they have for victory!

*Gulp*

I'm in an A/T alliance now. It's successful, so long as Austria can play Turkey and Russia against each other enough to gain the upper hand in terms of number of SCs.

AT is better for T than RT because you're going to be the one stabbing rather than the stabbed when it comes to it.

Sorry, I'd misread AT as AI :P
AT is great for T yes, and often risky for A, but if it works out well then Balkans can be DMZ'd, leaving breathing room between the nations and reducing the chance of a stab.

I have to say i've never had a long lasting A/T - but i think it depends, T as a naval power not going beyond the black sea / sevastolop, and A as a land based power not going south of venice can help both stay out of each other's ways.

But both get chocked, this turkey can convoy to france/spain when the time comes, but will have trouble if it can't get into the atlantic, and Austria can head north but get stuck in Moscow Livonia without a northern fleet.

The other option is swapping who is the naval power, and who does the land thing (or anywhere in between) but it still suffers from the same issue - this assumes Austria can't cross into Germany or England/Russia can't be convinced to use their northern fleets to help extend beyond those limits (an army in finland to secure scandanavia...)

still with any stalemate it becomes easier for either to win by stabbing the other.