Hi Netengineer10,
I can’t speak about all the toppers that you mentioned, but I got the Seven Comforts mattress topper for my own Ultimate Dreams mattress and love it. I did a review of it here on this site and also on Amazon. I got the king sized one so my review doesn’t show up on the queen sized one.
I’ve owned it for about a month now and purchased a second one since I liked it so much. I also got a pillow by Seven Comforts that I just finished my review on and posted here. There are also pictures of the latex ‘micro-rods’ that are used in the topper in the links on the pillow review.
Since the squares are pretty well packed with the foam (most of the pieces are uniform), they compress more than disperse under your weight in my experience. Also, squares are not very large so the latex rods don’t migrate around too much. I think my king size one is about 7x7 squares. It’s hard to count them through the sheets. 
I’ve had my topper for about a month now and still love it. There has been some softening where we sleep (the squares on the edge feel a bit springy-er) but I feel this is pretty normal. When I change the bedding, I rotate the topper and all the squares spring back to a pretty uniform loft. My husband loves it since it softens the pressure point on his shoulders when he sleeps on his side.
This topper is very very soft. I use a body pillow for support under my hips/back when I sleep on my tummy. I like it when I’m on my back or side. If you are looking for cushy softness this topper is really great.
Anyways, there is my 2 coppers. I’d love to hear your experience once you purchase a topper. I almost got one of the mattress.net toppers myself but took the chance with the Seven Comforts one. Good luck and I hope you get something that works perfectly for you.