I'll add my voice to those who are supportive of the slightly-refreshed 35/2 model.
I've wanted the old FA35/2 for some time now, but it has been prohibitively expensive in the UK (why, I don't know), and used examples don't crop up that frequently - which only made me want one more, since people obviously tend to keep them once they've bought them
With the HD FA35/2, we're getting a really nice upgrade with the HD and SP coatings. Those will improve flare performance and durability, as well as - I would guess - adding a little extra contrast (I say this based on my experience of my HD DA Limiteds compared to my FA50/1.4). The improved, raised texture of the focusing ring is also a welcome improvement, as the untextured ring of the FA35/2 and FA50/1.4 isn't ideal. Finally, the mildly-textured finish of the body parts is less likely to show up scratches and wear. Not an important consideration in functional terms, of course, but a nice touch for those who intend to use the lens in anger. Plus, the overall look is a little more in line with recent Pentax bodies and lenses.
So the improvements, whilst relatively modest, are significant. But the best part is price... When you consider what you get for US$399 / GBP £399, it's an awful lot of lens for the money.