Seems like I lost a lot more cranks on the Fireline than the PP. This was when it first came out. Like I said, Spider wire was the first and I think it was 100% spectra, and Berkley couldn't use the exact product due to legalities. The super braids take a while to get used to, but when you tie the right not, and trim the line consistantly, you believe how hard it is to break. I'm amazed at the stuff I've pulled up. To be fair, I've stuck with SpW and PP and haven't used Fireline in over a decade.
The reason not to use 10 lb mono is the line diameter is not larger than 20/6 braided. You get twice the strength with about half the diameter. That equals a lot less line to let out, a lot less. A buddy of mine uses the 10/2 and he lets out even less line, thus its a lot easier to troll in 16-18 fow.