I'll tell you what I like but it's just what I like.
I have a Kestrel and a Mantis. I bought the Kestrel because I thought it was built like a tank and it is, I got the Mantis because I a lot of guy's love it and it's extremely lite. Of the two the Kestrel is my favorite because it is like has a shape and cups my butt so it doesn't move around, I even took the leg straps off because I don't feel a need for them. The Mantis is very light and because of this it's like a limp piece of mesh cloth, I like it and won't get rid of it I just prefer the Kestrel most of the time.
I have Sticks, stepps, bolts, Ladder sticks, and Lone Wolf Hand Climber Seat. To be honest I use them and like them all, they all have a time and place.
Ladder sticks are the worst to drag though the woods but once up the easiest to climb I only use these for presets..
Bolts I really like bolts because they are light, and I don't think a thieve will find them but I don't like climbing them or taking them back out of the tree and they may not be legal in some areas.
Sticks are great for that tree with limbs that you just have to use. They are up there with the laddersticks as easy to climb. Depending on what you get they can be heavy and sometime difficult to carry through the woods.
Stepps, I really like these and some times I use them for the first few steps in conjunction with sticks so I can take them out with me but I don't like to carry more than four because I feel they start getting bulkier. I don't use them for climbing otherwise.
The lone wolf climbing seat is by far my favorite. Simple, it's lite, it's quick and quiet and I like the fact that you can't climb without being attached to the tree at all times! The only issue I have is getting around limbs. I'm still working on that.
Platforms
I use Stepps, The Predator and The Lone Wolf hand climber.
Love them all but you can't beat using the Lone Wolf as a climbing method and platform.
Side note. I traded my Predator for the Mantis because I really I really love the lone wolf. I also picked up some squirrel steps that I want to experiment with on the LW for the back side of the tree.