What camera are you getting?
Since you're new to Pentax, I'll just make sure that you know that the
DFA 28-105 is a full frame lens, so it is really best suited for the K1 or K1ii (or someone who will be getting one of those at some point in the future).
If you're getting any other Pentax DSLR (the rest would be APSC), the 28-105 may well not be your best choice. It will work just fine, and is a great lens by all accounts, but it is heavier and somewhat more expensive than some options (due to being for FF), plus lacks as wide an angle on those cameras with their "crop factor". Something like the
DA 18-135 or the
DA 16-85 (which isn't actually smaller or cheaper) will be more specifically suited to APSC cameras, and both are also great lenses.
Again, nothing at all wrong with the lens you're looking at, just want to make sure you know your options.