Originally posted by m8o aren't many Pentax lenses often re-skined/re-branded Tokina lenses?
p.s. the two photos are taken @ different zooms levels as well; not saying new isn't better, but should obviously compare two images of the same focal length.
No.
All of the manufacturers do co-development work on optics, and sometimes this ends up with first party and third party lenses with the same optical formula. However, if it doesn't say Pentax on the nameplate, it doesn't enjoy Pentax SMC coatings, and there may well be other internal build differences.