A rebadged Tamron cannot be a D FA* lens. It simply cannot meet the constructive requirements - even if its Jun Hirakawa-designed optics are up there.
The Nikkor 24-70 f/2.8 is $2400, a Pentax D FA* 24-70 f/2.8 would have been priced similarly.
I'm a bit upset about this rebadging stuff; Pentax should strive to become again a leader in optical design, not to outsource it. I hope we'll see some very nice Pentax primes next year, or else my level of grumpiness will get upgraded.
No "I'm jumping ship" though, doing it won't get me Pentax lenses.