I've rucked with a buddy who does all of the Go Ruck events. I'm not into paying for workout competitions but I do ruck around town with him from time to time. They have all of the official gear and claim it's very good quality gear.

He's a firefighter, ex-military, does marathons on the regular and as a side hobby does Crossfit. lol He signed up for some 1,000 mile challenge for 2018 and was at like 700 miles already in June. The guy just never stops. At any rate, he and his wife do all of these events and just did a 30 mile ruck two Friday nights ago and have like a 50-mile ruck coming up soon.

I think you can get gear close to what they use that will work but from what he says if you plan to do it regularly you'll want to spend extra to get the gear they use. He says that the packs specifically are worth the price tag if you do these events regularly.