Just throwing out some thoughts here. I know Timo has high standards and is trying to make 1.0 bug free before calling it 1.0. But I want to argue for an earlier less perfect 1.0.
Dovecot is already way past the quality of most 1.0 releases. So it is good enough by common standards. No one really expects a 1.0 release to be perfect. But - some people don't consider a product ripe until it reaches 1.0. Once you cross the line then more people will pick it up and you will get more bug reports because of a larger base. This would actually accelerate the debugging process. And it will spur acceptance of the product and perhaps bring in more developer resources.
Generally 1.0 is still buggy. It is usually followed quickly with 1.0.1, 1.0.2 ... and then stabilizes. Then as more people ask for new features it spawns 1.1.0 which is somewhat buggy and then 1.1.1 and by 1.1.2 it's rock solid.
So - I'm not suggesting Timo go to 1.0 immediately. I'm just saying that I think it's pretty ripe and sooner is better than later.
My 2 centz ...