Frankly I have not noticed a difference as far as the fish are concerned, braid or mono, fish are instinct feeders, competing for food and will strike darn near anything in front of them that resembles food when feeding. Plus upper coast and La water is typically not so clean that a trout swims up to the bait and says "ah I see line--see ya, lol". It's really personal preference, I personally like to use a 4 r 5 foot 20 lb mono leader tied to power pro super slick 8/30 with back to back uni knots. But have on many occasions tied directly to braid.
I have a lot of confidence in fluorocarbon leaders. Fluorocarbon won't foul on split rings or treble hooks. It's pretty nice around oyster shell or barnacles being able to stand up to some contact with that stuff. It can survive at least some of the encounters with sharp teeth fish like Spanish mackerel or bluefish maybe long enough to put on a POS lure, some wire leader or move for the next cast. I know there isn't a less visible option, that nothing else will blend in better with water than fluorocarbon.
It is just enough of a shock absorber to tone down the downsides to no stretch braid. I find it much easier to tie on terminal knots with fluorocarbon leader material versus braid. You aren't constantly chipping away at the braid on your reel spool by changing lures. The fluorocarbon leader takes the brunt of the loss. For me, the worst part of the fluorocarbon leader to braid set up has been the knot joining the two. On occasion, I've had that knot hang up in tiny rod guides and end up launching my topwater with the leader into orbit on the cast. I think I've solved that by carefully trimming the tag ends on the Albright special knot and putting a tiny drop of UV cure adhesive on the knot. The uv glue on exposure to ultraviolet light forms a smooth very thin shell over the knot so that it will pass through the guides without issue.
I have done the straight braid and I've done the braid to mono/ fluoro. They do both work in the waters that I fish, but I much prefer 20 or 30# power pro with a 5' 25# mono or fluoro leader. I prefer this for many of the reasons already mentioned. I tie a loop knot on any lure that doesn't have a split ring to get more action out of my lures, that won't work with braid (I don't use clips or swivels). Straight braid to anything with a treble hook would be a nightmare to untangle with a fish that gets the line twisted up!
They will hit a lure tied directly to braid even in some very clear water. I've been with sightcasters like Railbird and I've done it myself. Winter water clarity and how finicky they can be in the winter might be a little different.. maybe in that ultra clear water. That said, 9 of 10 times Im still using a leader for the reasons mentioned above. Braid can slip out of the eye of the hook/lure, Many times braid is less resistant to being cut by teeth or gill rakes. If your braid gets hung in a split ring like karstopo said, it's a pain in the arse. many more above. The only time I tie direct is when I don't have time to tie a leader for some reason, or if Im wading and forgot to bring extra leader and need to re tie, and sight casting from a tower where I want to hoist the fish in from the tower.
For me, the worst part of the fluorocarbon leader to braid set up has been the knot joining the two. On occasion, I've had that knot hang up in tiny rod guides and end up launching my topwater with the leader into orbit on the cast.
Another solution is the FG knot. I recently started using this and it is fantastic for use with micro guides.
I use fluorocarbon or mono leaders with my braid most of the time. On occasion, I've tied jigs directly to braid and caught fish.
I switched from the Crazy Alberto to the FG knot awhile back. I use long leaders and the knot always passes through my rod eyes. I switched to the FG knot because I found that it glides through the eyes smoothly. With the Crazy Alberto, I always had some knot pop when it came through the eyes. IMO, that little pop robs a little distance off of each cast. Also, the FG knot, when tied properly, is super strong.
Tie fluorocarbon always to braid for several reasons.
It's stiffness is better for working a topwater.
Needed to leader in a fish. Wet braid will cut your hands if the fish decide to run.
Invisibility in clear water, a little stretch.
Winter / clear water for Trout 10# to 15# FC.
Spring / summer 20# to 25# FC.
10# braid for Trout & Reds for longer cast using 6 turn Uni to Uni knot.
Fishing heavy structure or surf 15# braid. ...... ICM