I got my tank from them a few months ago. It is still cycling so I can't give you a fill answer, but I can help. Mine is SF glass on the front, and I can definately tell the difference when I look through the side vs. looking through the front. I'm going to put an insulation panel (covered in black vinyl) on the back of my tank soon, but for now I can look through the back and see the white painted wood shutters behind the tank. There is a definate, but slight, green tint to the white shutters when I look through the tank compared to the color of the shutters next to the tank. HOWEVER, if I didn't have the SF glass right next to the normal glass, for comparison, I would probably not notice a green tint. All things considered I'm glad I went with SF glass, because:
1) Glasscages.com uses thicker glass than most (3/8" thick for a 25" tall tank) so the green color would be more noticeable than if the glass were thinner.
2) Glasscages has a really good upgrade price. The front of my 65 gallon tank (36" x 25" front) only cost an extra $45 for the Starfire glass.
3) Unlike a reef tank, which blasts bright white light into the tank, an octopus wants much dimmer light. I wanted to be able to see my octopus clearly, and see its true colors, without having to pump extra light into the tank to do it.
I love my Glasscages tank (although I found the people there to be touchy and hard to work with). I decided to build my own stand instead of buying one from them. My stand turned out great, but it cost as much in materials as a stand from GC would have cost, and it took me a long time to build. Consider getting your stand from them.
Just a heads up, Perfecto(Marineland) jsut came out with a Starphire line of tanks..... 150g(which is basically 36" cubed), 200g,250g, and 300g... all of which are 36" width to my knowledge(you can get them w/o starphire glass)