Marc, you and many others, may find interest in the YouTube channel HowKnot2. He break tests climbing gear, mostly rock climbing, but there's lots of cross over as well as some arborist specific content.
I like my Massdam, it recently rescued my wife's Hyundai after the winch battery refused to supply power long enough to get it on the trailer. Massdam has power for just as long as I do. Although it must be said that they can and do slip, and need to be minded a bit better than it appears at first glance. Still, for the price, weight and size, it really is hard to beat.
Folks are we going to call a PortaWrap essential or non? I mean, technically I don't have to have it, but I will not use the tree for friction, haven't since I bought the thing. It's just nice to have consistency, I guess. Also, my ropes last sooooo much longer.
I also attach it to the back of my truck via a large shackle, and "bollard it off" as my wife calls it, so I don't have to tie and untie midline knots when we're truck yarding logs out of the bush.
In all it's just been way more useful than I ever thought.