Well what are pros and cons for the Predator platform?
The Mission is 18" wide by 14" deep and weighs 5.4 lbs. The Predator is about 12" by 12" and weighs 3 lbs. (The Predator XL is 15" by 13".) Relative to the Trophyline Mission, the Tethrd Predator Platform is much lighter and more packable, $20 cheaper, and is currently in stock. I haven't used the Mission myself, but from pictures and other folks' reviews, it seems the Mission is more comfortable for guys with size 12+ feet, is easier to shuffle around on, has better contours around the edges (need to wrap/cobra weave the Predator with paracord to make it grippy enough, in my opinion), and has the nifty little step on top of the post. I think the Mission also would be a smaller leap for traditional tree stand hunters making the switch to saddle hunting, but I've honestly had no trouble adjusting to standing on the Predator.
Both are great options, and both have strong resale value on here if you try one out and decide to go a different direction. If I had to recommend one, I'd probably recommend the Predator because it's in stock, and while I'm no ounce-counter like some folks on here, 2.4 lbs. is a difference you can feel in your pack (or especially if suspended from your saddle). If you try the Predator and dislike it, you'll get most of your money back by selling it on here and can put that into buying a Mission.
Hope this helps!