I used Nanofil, 6/2.  And well, it snapped on me setting the hook.

 

So Walmart had certain poundage Fireline for $5, so I bought 6/2 poundage.

 

I feel both lines and feel similar.  

 

So, what's the difference?  And is Fireline better than Nanofil???

If you are getting breaks way below what you would expect with nanofil, I think you may not be using the right knots.  Nanofil is very sensitive to having the right knots properly tied.  More so than any other line I've ever tried. But my experience is that when the right knot is used it is a good line.  The only advantage that nanofil has is that it is smoother through the guides than braids.  If that is not important for you, don't bother with its knot challenges.

Similar, but different.

 

"It's made of Dyneema (a gel-spun polyethylene), which is the same sort of material that's commonly used in bullet proof vests, windsails and Berkley's other superline - Fireline.  

The difference between NanoFil and Fireline is that NanoFil consists of hundreds of Dyneema filaments that are molecularly bonded together, not fused together by heat like Fireline. The idea behind NanoFil was to create a line that has the strength and no-stretch, no-memory properties of a braid while retaining the smoothness of mono."