Dumb question but - for punching only or kicking and punching?
We used to use both styles for kick boxing, however the standalone weighted punch bags worked really well - even for kicking. The only thing is they don't move, which is good for half torso as it makes you adapt - however we did a lot of sparring which solved that.
How heavy is the bag you're putting in? There's no indication on the specs of that the maximum loading. i.e. if you clock it one from the side is it going to fall over. The reason I point this out is that you should still be using your footwork to move around the bag.
That's purely some opinions/thoughts from doing 3 years of kickboxing (5 nights a week).