Monkey if you are referring to the pics in my gallery that is of my 100 gallon 5ft tank and yes it was tonga branch, and I love it. I ended up giving it to my girlfriends mom to get started, but will soon be getting it back. Now I have a 75 setup and like it ok, but would like bigger.
If I was you and you are already in a 58 I would go as big as you can. I think if you could find a 5ft 100g you would be in good shape. It wouldn't have the height of the 90 and would be a foot longer, but by all means if you can get a 90 over a 75 get the 90g imo. I really like the view of a 90. It may take a little more light though. Also in a 90 with 5-6" of sand you will take alot of the height out. Zoos on bottom, lps midway, and sps up top...