I have had similar experience with that line. I have pretty much stuck with Sunline for all my Fluro and have been pretty happy with it.
I have also had very good results with both segar red and stren fluorocarbon in 8 # test for leaders on my spinning reels. I use 10# braid with about a 15 to 20 foot leader as I can retie many times with out having to retie a new leader.
The Sunline Super is only $14.99 and has served me well though, so not sure I will ever change.
I just found out Sunline makes Gander Mountain house brand. Anyone use it?
I have used XPS for several years and really like the stuff, but the price has gone up $10 a spool in the last 5 years. $21 for 150 yards is a bit steep.