Allow me to try a different approach:

On the issue of per diem, ABX has a unique system in that it is based on per day rather than per trip hour. The key to getting per diem is that you must land at an airport other than your domicile. If you fly a quick KCVG-KDTW-KCVG "mission" just to pick up some auto parts, you will be paid a full day per diem, even though you just had 1.5 block, and maybe all of 3.5 TAFB ("Time away from base.)" On the flip side, you could be asked to ferry a plane to anywhere because of a broken airplane, then recalled back to base because the airplane just got fixed and blocked out. Even though you may have flown for 8 hours, you'd get zero per diem for that mission. I've done both types of flights (well, not the 8 hour turnaround , but you get the point), and it all comes out in the wash when the fat lady sings.

Now that I've covered the nitnoid aspect of per diem payment, the big question on whether ABX might be a good career alternative for those who can't break the Brown or Purple code remains. ABX, Atlas, etal, are ACMI carriers. ABX perhaps "less so" than others because of better compensation and certain work rules. DHL and Amazon flying could be considered more conducive to predictable, consistent schedules (and thus line construction), ACMI flying less so. I would estimate that ~ 2/3 of ABX aircraft (and by implied extension, flight crews) are primarily, or exclusively dedicated to flying on DHL, or Amazon type runs.

One might try to infer that 2/3 of ABX schedules might look like FedEx/UPS schedules, or a graveyard shift mirror image of regional airline flying, NOT. The first big hole in the cheese is that ABX CBA is constructed to ACMI like work rules. How does having 50% of lines constructed to 17 consecutive days on the road grab you ? Yes there are some lines that more closely resembles the week on week off from the good ole days. Thing is, ACMI flying gets mixed in with DHL/Amazon type trips. That can play havoc with sleep schedules.
Plus new hires can figure on being on reserve for a spell, until you're out of the bottom 20% or so. Lastly, this analogy may help for evaluating long term career questions. If you're the type of individual who considers consistent predictable patterns like a scoop of ice cream, and irregular schedules (ACMI) like a scoop of dogs#^t: Even a serving of 90% ice cream, and 10% dogs#^t will still taste like dogs#^t. HTH..................