a root rake would be just that; a rake to push through the soil with no grapple. a brush grapple or a root grapple will be more like a bucket, it will have a floor that allows dirt to filter through, but yet traps the sticks, roots, stumps and other trash while you push foward with it.
you want a grapple that has greasable hinge points with captivated hinge pins, and half-inch tines. beware of some of the lighter, cheaper built grapples on the market, they only have a bolt and a flat plate with a small bolt for the hinge point. the cheaper ones also have the cylinder hoses exposed instead of routed within the steel of the grapple tubing. this certianly won't last long in a enviroment such as land clearing.
another important item to consider on a grapple is width in relation to the width of your machine. you want a grapple that is just slightly wider than the width of your tracks. this will deflect any objects away from your expensive tracks and also clear a nice level path for your machine to run on. i have a case 70xt, it measures approx. 73" wide and i have a blue diamond extreme duty brush grapple that is 78" wide. works out perfect.
some of my favorite brands: loflin fabrication, solesbee's, blue diamond, midwestern attachments, construction attachments.
also consider trying a "4 in 1" clamshell bucket. i have a 4180 midwestern 4 in1 that i use to pull up cedars and small trees. i raise the bucket, open the clamshell, fit the bucket down over the tree, close the clamshell on the tree, then pull the tree out of the ground. works excellent for cleaning out fencelines without destroying the fence.
construction attachments has a nice "4 in 1" bucket designed specifically for high hp ctl's. they also have a skeleton bucket with an optional add-on grapple that i want to try out. hope this helps ya out.
