So I've been on these for a while and been happy with all of them.
8, 10, 15# - Seaguar Red Label. 200 yard spools of "spool filler" fluorocarbon but I refuse to buy tiny premium spools of fluoro. This stuff works fine. And I've taken to using it in the surf for stiffness to avoid c-rig tangles. 10-15# section from braid through sinker to swivel, 8# leader to hook. Or put that 10-15# directly to an LC/lure. I wish they made heavier than 20# for this stuff cuz it would easily become my only leader material. I also love that it's the only budget fluoro spool I've found that has a line keeper. InvisX is nice though not stiff at all, but doesn't have a line keeper so it inevitably unravels and makes a mess.
Another note on this stuff, when I was a deckhand during the mahi bite, I was quietly tying 6' 20# leaders of this stuff from my own collection onto the rental rods and they did get bit more during tough days. I'm skeptical about fluoro, especially cheap fluoro, but it definitely paid for itself via fillet cash on those days.
30# - P-Line Fluoroclear. This is the heaviest they make. I use it for 95% of my inshore boating leaders. Fluoro coated mono, and as far as I can see it's the only one like it anymore on the market. Used to be a competitor or two....Super cheap filler spools around $10-15. Works. Gets bit. Strong enough to horse a tail hooked T to the boat, never break off unless there's heavy structure. I was using it in 6# for surf leaders but I eventually went with the Red Label for stiffness as it tangled way too often, compromising strength. Also have used it in 15, 20, and 25 with success, but 30 does it all here so I keep it simple now and pared down. It's a really great supple line for if you wanna fill a spool, too.
50, 80, 100, 120, 150 - Ande Pink Mono. Old news that off color mono disappears in water better than clear mono. 50#+ fluoro leader is all insanely expensive so I don't touch it. All my bigger presentations are either for sharks or reaction bite type stuff for pelagics, so it's not super important anyways. Also this stuff is soft enough to tie SD Jam knots no problem all the way up to 150#. 2 turns and you're good.
Reason I wrote this out was a reminder from this morning. Koga recommended to me a while ago to try the Seaguar AbrazX 12# for spotties. Definitely some hardy material for structure. I went ahead and ordered it, kept it around. He mentioned actually filling the spool with it. I don't like doing that so I tried tying short leaders with it. Literally snaps every single time I ever cinched down a uni-uni knot, totally bizarre. Switched to a modified Albright and it's done fine, then this morning I made my 100th cast of the day and it popped during a lob cast. Thankfully the LC just kinda fell to my feet so I was able to fish it out but, for whatever inexplicable reason it has incredibly mediocre braid connection strength. Sticking to the red label. I'll fill a baitcaster spool with it and try it as originally suggested eventually but it's retired from leader duties.
Anyway, take what you will from all that. For the most part it's a system that's budget friendly and works for me, but mostly because I don't need heavy fluoro for live baiting pelagics, nor do I tournament fish for bass or anything else. Otherwise premium fluoro might end up making sense.
Curious what you guys do.