I own a BOB XL. I bought it because I can’t hang a bag in my house nor use a bag hanger frame thing.
Everything’s got its limitations. The cheapest and worst hanging bag isn’t better than the absolute best freestanding bag. Quality varies. Hanging bags are TYPICALLY more durable, longer lasting, and can be hit harder than freestanding bags. Hitting them harder develops more power. If you hit many freestanding bags with full force, you’ll hit the inner core.
A well designed and filled freestanding bag doesn’t topple over very easily when hit right, contrary to popular opinion. The people knocking them over (when they’re properly filled and designed) are typically pushing them instead of striking them. Side kicks by nature are more of a driving kick, so they’re an exception IMO. Same for running and flying kicks. If someone is knocking over a freestanding bag while punching correctly, they’re either Mike Tyson or hitting too high up on the bag when it’s raised high, and physics moment arm type stuff takes over.
People bash freestanding bags because they’ll topple with a good side kick or flying kick. A hanging bag will swing all over the place, so IMO it’s really not much different.
All things being equal, I’d opt for a hanging bag every time. When the day comes that I live somewhere I can hang a bag, I’ll get a good Muay Thai bag. But I’ll also keep my BOB XL. There’s things I can do more effectively with the BOB that I can’t do with any hanging bag nearly as well - uppercuts and specific strikes to specific areas.
And for some reason, going 12 rounds with my BOB XL is far more motivating for me than with any other bag. I can easily tell if I hit my specific target rather than approximate it.