I don't have my FA* and F* lenses because of a strong belief in a Pentax Full-frame digital making an appearance any time soon (although it would be nice) and I don't own them to look cool or for nostalgic reasons - I have them because they produce beautiful results and in general the focal lengths work for me. As for repairs, yes that's a chance you take, but your chances of buying a DA*16-50 or 50-135 that will need a repair are probably higher than with an FA* lens - but if an FA* lens does need a repair you may well be out of luck
The comment has been made that there is little turnover of FA* lenses, I suspect this is due largely to the fact that many who acquire them are more than satisfied and so keep them. The 24mm does seem to make an appearance second hand quite regularly, probably due to a larger number being made and also the fact that there are some copies that are softer than others (I had a poor copy a while back) and so they get recycled into the Used market.
I owned the DA*300 at the same time as the F*300 (essentially the same lens as the FA* version I believe), when it was time to sell one I deliberated hard and "on paper" I should have kept the DA* - WR, faster aperture, quieter focus, etc - but when I looked at photos taken with both I preferred the "look" of the photos I'd taken with the F* version.
Don't get me wrong - I'm not a FA*nboy of these lenses exclusively, in the longer zoom range I prefer the DA*60-250 to the FA*80-200. The DA15mm Ltd is beautifully crafted and delivers great results, and the DA*55 is a superb descendant of the FA*85 - but the F and FA Star lenses are still very relevant in todays digital world