This will always be a subject for contention as it comes down to personal choice. there are different applications for different line. Mono for cranking is a standard, however I have learnt to use braid with a flouro leader (personal preference) I find it a lot easier to feel the action of the lure. A single blade of grass caught on a hook can totally change the action of the lure, however I have had to learn how NOT to strike so aggressively, it becomes more like a gentle pull than a strike.
for grass beds and lilies, braid is by far Superior. It is the most sensitive out of all lines, it cuts through the grass and it is half the diameter making casting a lot easier i.e P line flouro 12lb = .29mm and suffix Y6 performance braid 15lb = .18mm. However one must also consider all the choices, someone mentioned "Fireline". Fireline is designed for spinning reels and for that purpose it is great but is about the worst braid you can use in a baitcater. in my personal experience I have found spiderwire to be good, viper to be very good and suffix Y6 performance braid to be the best.
Flouro I have used Vanish, P line, Siglion, seagaur even awi-shima and found them all much of a muchness, but I do retie my line often so dont really give the line a chance to fray or get abrasion burns, vanish was my least favourite at first (I even swore never to use it again) but once you have mastered casting with it I now find it the best. Personally I couldnt recommend one, you wont go wrong with any of the above.
Just a note to the people who have only ever used mono ( I did for 3 years before I started palying with other lines and then took an expensive learning curve ). The feel of flouro and braid is a lot different to mono, it is a lot more sensitive and you tend to feel a lot that you never did before and you often end up striking at rocks or grass because they feel so much more there. Dont give up, practice and you will be able to eventually distinguish between rocks, branches and grass. Also with flouro especially the line is thicker and generally stiffer than mono and you will have to get used to casting with it, expect a couple of overwinds but dont get dispondent, once you have mastered it you wont look back.