hi guys. i replaced my Big 5 Century 100lbs canvas heavybag (the filling was very hard) with the ringside 130lbs water/foam heavybag. http://www.ringside.com/detail.aspx?ID=25874 now, i like the fact that it's real soft and safer on the hands, but there is one thing i noticed. the ringside water/foam 130lbs bag moves around WAY more when being punched. when hitting the big 5 century 100lbs canvas bag, it didnt move as much. i'm guessing, even though the water/foam bag is 30lbs heavier, the fact that it's filled with water makes it move more? any thoughts? by the way, i want to get the regular ringside 100lbs leather bag, anyone have experience with it? and is it soft filled? (leather 100lbs) http://www.ringside.com/DETAIL.ASPX?ID=25262 and why does the ringside "powerhide" (non-leather )100lbs bag say it's "soft filled", but the 100lbs leather bag doesn't? is it just a typo? (non-leather 100lbs) http://www.ringside.com/DETAIL.ASPX?ID=24793 thanks.