This thread isn't about validating existing K4 pilots choice. It is about the viability of ACMI vs ULCC for prospective NEW employees. You are correct in saying that "Kalitta has become a career destination for most guys." However this isn't for the typical reasons one might find with other career destinations. The top third of the seniority list is your old fashioned ACMI crowd who isn't going anywhere. Next you have a large crowd of people who got hired during rapid expansion and went from an RJ to 747 CA in two years and now have golden handcuffs. Between 4-600 you'll find lifer ASA guys who were content at a regional. These older folks are even more content here at K4 and aren't going anywhere. The bottom of the list is a revolving door.

So I'd say this to a prospective young new hire. Get your PIC first. Go to a ULCC or higher tier ACMI with rapid growth. Keep your big 5 updated. If you're happy hanging your hat at a second tier company I'd choose a ULCC/LCC. The ACMI world is much like the regional world where the individual carriers serve their masters and todays victor will be tomorrows loser. Look at ATLAS and ABX.