You mean like the "Bobs",(Body Opponent Bag) mannequin looking ones? Idk it's maybe just me, but they seem too stationary for me. I like the 100lbs heavybags from Tko or everlast personally. A heavybag with its cylindrical shape kinda forces you to hit it more accurately than a "Bob", or your punch will just graze the bag. I also think its better for helping you with infighting too, even with a 100lbs bag you can move it around abit and move yourself around it punching from different angles. Can't really do that with the Bob. I've used the Bob just not for me. Just my .2
Free standing bags do have their limitations: they don't move too much so you aren't practicing hitting a moving target. They will however slide across the floor a little bit, some have a spring attaching them to the base to reduce this. They aren't my preferred heavy bag.
Free standing bags are useless for fighters. They are okay for people that 'do kickboxing' or whatever as a hobby but for proper bag work they are rubbish. The bases are too bulky and can get in the way of footwork, the bulk of the weight is too low and the bag itself is too soft, generally they are a squashy foam cylinder on a plastic base that fills with water or sand.
I have a b.o.b, they're ok for practicing accuracy, and bodyshots, good for hooks and ok for uppercuts, (elbows and headbutts too!) but IMO they're pretty crap compared to a traditional heavy bag, as they don't swing around (can't practice footwork while using them) and feel insubstantial when you hit it with a heavy dig, they're also sore (from friction with the rubbery stuff they're made from) to punch without gloves They are great for dressing up and scaring the **** out of people!
