I'm using 10 lb Fireline to a 10 lb fluoro leader. Seems to work well for what I'm targeting.
I've recently started using braid after using exclusively mono line. Bear in mind I fish ultralight/finesse spinning exclusively, so my experience might not mirror others.
At this point, I personally see no benefit to using braid. And it was rather difficult to find a braid that could cast similar distance to mono throwing lightweight presentations. Most braids didn't feel "slick" and I also wonder if the micro eyes in my rods were partially to blame for disappointing distance.
I finally settled on Spro Finesse Braid. It's very "slick" and casts very well. Sadly, it's hideously expensive. And those same micro eyes proved problematic for leader knots. I settled on a tiny knot favored by carp fisherman (they use 4lb test with 8-9 foot rods with micro eyes). I figured if it was good enough for 20+ pound carp, bass should be fine. And thus far that's been proved out. That being said, I prefer no leader...until I get a long distance snag at which point I wish I had a leader!
As far as performance? I'm strictly in the "meh" camp. I'm just not seeing any benefits in my fishing. My rods are already fantastically sensitive so any benefit from the line is incremental at best. Sure, I can definitely feel less stretch than mono, but I don't think this has helped...or hurt.
So for me, I don't think braid has improved anything for me and the cost is prohibitive.
As with all things, YMMV.
