I went with the Tree Slayer. The 2 main reasons were that it is wider than the mulcher and there are a lot of rocks on/in the ground here and that would ruin the mulching teeth if I got too close to the ground. I use it for brush cutting the sides of ponds, making and maintaining trails and cutting over hanging branches by field edges etc. It works really well.
I assume that you have a cab on your machine? I don't have the plexiglass but am considering it. It will throw debris towards the cab, mostly from it ricocheting in my experience. Scares the crap out of me sometimes, lol.
If looks like if you went with either one, there's an option to add the blades or mulcher to it. It does add weight to the tree slayer which does make a difference when you're on sloped ground or reaching out over the side.