I'm sure if you google around you'll find some articles but, from my perspective as an aerospace engineer who used to work on C-130s: It's an absolute workhorse.
If you've ever been up close to a museum fighter plane, they're in good shape. The leading edges are all smooth and polished, everything is sleek and in good condition. Line Hercs are not that. They're usually dented and covered in carbon from the exhausts. The leading edge of the wing is like three feet thick. It's a Mack truck with wings held aloft by furious amounts of horsepower.
It's dependable, reliable, and versatile. These things survive being shot at, being landed on gravel, ingesting birds into the intakes, ingesting sand into the intakes. You can start a Herc by putting another Herc in front of it and running the engines up so that the prop wash buddy-starts the aircraft behind, like bump-starting a car rolling downhill.
There are dozens of variants from the gunships to the EC-130 Compass Call and friends which carry serious business ELINT gear for secret squirrels to do secret squirrel shit with. You can put RATO pods on it. You can use it for SAR. You can drop bombs from it (and not even by throwing them out the ramp, which you could also do). You can use it to refuel fighters and helicopters aerially. You can put skis on it and land it in the show. You can parachute from it. It's not a jet, but despite being a draggy brick of an aircraft it'll still pull almost 0.6 of Mach while carrying two hummvees. Also, those hummvees can parachute from the aircraft.
There's a reason it's so widely-used [0] and that reason is because the Herc is groovy. It's the unsung hero of nearly every military operation carried out by NATO and friends since the 1960s.
I don't think I've ever read that before, do you know of anywhere I can read more about why that is?