I couldn't resist giving this stuff a try. Last year I picked up 2000M of 40# 4-strand Spectra PE Extreme Braid and 1000M of 40# 8-strand Hercules PE Braided Line from Ebay but they have the same brands on Amazon. 3000M of braided line for less than $60 was just too tempting of a deal to pass up.
My intention for this stuff is to only use it as backing for my planer board lines and when it came time to replace backing this year on some of my reels, I used both of my spools to put 800-1000' of fresh backing on each of my planer board reels. I wanted to fill these reels up to maximize the efficiency when reeling in these long lines. With the more expensive braid, I tried to be conservative and only put 600' of backing on my reels which never filled them up. The first thing I noticed is that it is significantly thicker than 40# Sufix Performance Braid & Power Pro, so they worked great to fill the reel on flat lines, and up to 7 colors of leadcore. However, for the full cores (10 colors), I stuck with my Sufix Performance Braid to make sure I could get 1000' of backing with the smaller diameter. I only use the Power Pro for my dipsy rods but have used a variety of braided line for my planer board backing - mostly Sufix Performance Braid and Cabela's Rip Cord because I was able to find bulk spools cheap offseason similar to what Pannie Popper said.
So far, zero complaints about this stuff....but I've also gone fishing twice this year. I definitely liked the 8-strand stuff better than the 4-strand. The 8-strand feels and acts very much like decron line and is very smooth. With both of the cheap brands, I was able to use my standard knots (palomar & albright) and they appear to be holding up well. Only time will tell and I expect to update the previous post I put up on this topic (
http://chitownangler.com/1fish/viewtopic.php?f=1&t=84458&sid=749c791d10f4861b502da2df2a503763) after seeing how this line fares throughout the year.
For now, I can't say I recommend it or not but I definitely would not dissuade anyone from giving it a shot.