Originally Posted by kristoffon 
If you took just "a", one, photo that's hardly evidence to put fault in the lens. Focusing this close DOF is so thin it's easy to shift the camera slightly between autofocusing and taking the picture and the result will be blurry and you'll wonder why. The second picture does look better but in your place I'd use a tripod and shoot a flat, perpendicular surfae to eliminate all doubt.
As you can see both images have DOF in the center so camera shifting is not an issue here.
Believe me I took many shots with this lens and I had to stop down to f/4 to get sharp ones. I posted these two because currently they are the only ones that are of same subject, which can show the difference between the two lenses. I could not get anything close to sharp even at f/2.8. I have the 21mm, 40mm, 43mm, 70mm, and the 77mm Limiteds and I pretty much know what to expect from the 31mm Limited. Of all the Limiteds 43mm is the least sharp wide open, but the 31mm assembled in Vietnam lens was so behind from what 43mm could deliver wide open. The new lens though is heaps better, actually it's perfectly fine for me.
Originally Posted by Darren M On a side note, I am surprised and heartened to see that they are assembling the FA Limiteds in Vietnam now. This suggests that they will not be disappearing from production anytime soon. I could well be wrong, but I don't know of any other time that some of the lenses have had their production moved and asssumed it wouldn't happen. This means that the FA Limiteds (and others) can go on, even when originating from different factories.
This is a very good point Darren. I also don't see why they should stop production of lenses that are so much in demand and fetch for a good price as well, and actually cause people from other systems to switch to Pentax.