i have had a grapple about a year, here are my observations.
I have the open bottom, Blue diamond with an L shaped. I think mine is a 60" which is smaller than my bucket on the 55 hp tractor. Mine does not have a completely flat bottom, but you can get under logs. I like that it is rounded inside because it rolls up brush and you seem to be able bale it up and pack more in there before driving it somewhere. I love my grapple for hauling already rooted material or brush. But in my experience the non-rake "L shaped" grapples are deceptively bad at rooting. In retrospect I think the "rake type" give you a lot more leverage for pulling roots of small trees because its on the strong part of the stroke of your bucket rams. What I do now is I use my standard tractor bucket to push the top of the tree over slightly. This pops up one side of the root ball, which I then push the exposed root with the blade. After I have a big pile of rooted trees/ bushes etc I swap to the grapple and haul a bunch to the pile. I use the grapple most commonly rotated further down than you would with a standard bucket. Kind of like a clamshell but not that extreme until it gets dumped somewhere. In my experience you could operate it like a clamshell and you really wouldn't lose anything. It all stays put really well. Sometimes too well. Mine has serated teeth on the tips for derooting and it catches lots of brush as I'm dumping it on a fire, which can make some tense moments. I would prefer to not have the serates.
All in all it does a wonderful job and I love it. I would swap for a root rake grapple if I could get an even trade, but I think the difference is not a big enough deal for me to spend any money to change.
OH afterthought, mine was designed for a skidsteer and when I first got it, it wanted to crunch my loader zerks until I cut a little groove for them.
