Hi Olrocker
The choice is yours, just simply toss a coin.....heads it's Pentax, tails it's Tamron. Either way you can't lose, because they're both brilliant all-round lenses which should suit your needs almost perfectly. The only time I ever remove mine is when shooting either landscape or interior architectural photographs with the equally astonishing rectilinear Sigma 10-20mm superwide zoom. I'm sure you'll have endless fun with whatever you eventually end up buying. Incidentally, in the USA the Tamron comes with a SIX year warranty !
Best regards
Richard
P.S. Try the link below for some examples taken with the Tamron 18-250mm:
http://www.pentaxforums.com/forums/85055-post8.html http://www.pentaxforums.com/forums/83871-post6.html http://www.pentaxforums.com/forums/83875-post7.html