normhead, why so serious? I get the idea that you think people may be misguided in their opinions, but they are in fact merely their opinions, to which they are fully entitled. You come across as someone who feels that certain gear is being unjustly maligned, and so you must "fight the good fight" on its behalf! As a result it seems confrontational, and I reckon it weakens your argument, even though I often agree with your basic points.
But I don't like to see other PF members referred to as jackasses talking crap, Joe Blow shooting off his mouth, or (especially) demands from a few people on this forum that people have to prove their opinions by posting proof, and so on.
Anyway, to return to talking about lenses
. I think the 18-135 is one of the best value and most versatile walkabout lenses on the market for Pentax users. HOWEVER, the reviews of the 16-85 seem to suggest that it gives slightly better IQ, but I wouldn't buy one, the 18-135 is more useful to me.
HOWEVER, I prefer to use my primes, or my Sigma 17-50 f2.8 coupled with my Penny 100 WR, because for me they give better results - that is to say, results I like better, and I also like using them more. (nb, my 18-135 IS softER at the corners from 100 up, but not enough to bother me, and it may be user error anyway! Softer than what, you may ask. Softer than ITSELF - on my copy, and in my opinion, the corner sharpness above 100ISH falls off too much compared to the rest of the range, so I prefer the greater consistency of sharpness offered by 2 different lenses. This is no problem, as it frees up the 18-135 to be almost permanently mounted on my wife's K30.)
---------- Post added 07-08-15 at 03:42 PM ----------
If I could afford it, I would buy a 60-250 to go with my Sigma 17-50, but there are two problems - it is far too heavy for lazy old me, and my wife has almost lusted for the 60-250 since she first saw one three years ago, so if I buy one, I have to buy two, or I still wouldn't get to use it! (I bought her a Tamron 70-200, but it fails in too many ways, lol - it's heavy, it's noisy, and it doesn't look impressive enough for her!)