I currently use 1.09 for production with simple two-level anti antialiasing. this seems to give me the best speed/quality. I have been learning 1.4 and have noticed that simple two-level has been replaced with adaptive QMC which seems to be quite different. I normally use settings of min 2- max6 thresh.05 for simple two-level. What settings will give similar quality for adaptive QMC? Why was simple two-level eliminated?
You will most likely need to decrease the Noise threshold in the QMC Sampler rollout to get a better result. If you can also post some images with the problems you are having, it will be helpful.
I lowered the QMC noise threshold as Vlado suggested and it vastly improved the image but it seems a little noisier than adaptive subdivision. I changed the noise value from .005 to .001.