I own the fixed and swivel version of the Model 25 Harris. The swivel version is definitely the way to go. I use them only for antelope hunting, mainly because there are few good shooting rests available in most telope country. But also because the bipods add substantial weight and bulk to the rifle. Any projection from my hunting rig grabs every tree branch or brush within 10 yards of my path! My primary reason for not carrying these great inventions on elk treks is that I've yet to shoot an elk when I've had time to sit/lay down, extend the bipod, adjust height, you get the picture. Most of my elk shooting has been quick with barely much opportunity to get the rifle to my shoulder.
Anyway, like a previous post said, spend the extra $20 and buy the swiveling model. By the way, don't mess with the prone versions for hunting. They work great from the bench or elevated prairie dog stand, but the grass and brush (sage) common to most hunting areas that require a bipod do not observe proper growth limits. Their height often requires shooting from the sitting and sometimes kneeling positions to see the game! Don't go cheap with your hunting gear.