I was surprised myself when I heard others were using fishing line... for a while I thought it was some classical guitar inside joke until I realized they were serious.
When you realize these fluorocarbon lines are essentially made of the same material that carbon guitar strings are made, then its not too hard to believe. If you've tried carbon strings before and like them, these seaguar premier lines are definitely worth giving a shot. They are my string of choice as far as carbon goes because they have they have the power, response and sustain of carbon while still having some of the warmth and tonal beauty of nylon, and they feel nice and comfortable under the fingers. They also are super durable and hold their tone for a long long time (I mean these things are designed to catch some big fish!). It's also really cool being able to tell others that your strings are made of legit fishing line after they've commented on how beautiful your guitar sounds. For those wanting to dip their toes in the world of fishing line I suggest:
3rd string - 80lb Seaguar Fluoro Premier 25 Yards Fluorocarbon Leader
2nd string - 60lb Seaguar Fluoro Premier 25 Yards Fluorocarbon Leader
1st String - La Bella 10PH or Augustine Imperial or Regal. Others here may have different suggestions for the 1st string but I personally think they blend well together. Many complain that carbon 1st strings tend to be too high tension, sound tinny, and are too thin which is probably why we have yet to find a suitable Seaguar gauge that works well for it. It's probably more of an issue of the material just not being suitable for the first string.
Some might be turned off by having to buy them on expensive reels, but it actually comes out to around $1-1.50 a string which is pretty average considering we pay $7+ a set. It will also last a life time and the 3rd string blends really well with full nylon sets without the tubbiness. However, if you've tried several brands of carbon trebles but have never liked them, then I'd skip on these.
"Success grants its rewards to a few, but is the dream of the multitudes.
Excellence is available to all, but is accepted only by a few." - Christopher Parkening