On my what home from the RISSA show, I stopped by a shop yesterday and pulled out 30# braid for PP, the new stren brain, Fireline stealth, and a couple others and had them lined up right next to each other...I wish I had my camera, there is a noticable difference.
I have only fished with PP braid (30 and 50) and have had good experiences with it both on spin and conv. The only problem I have is if you do get a backlash or windknot, it is more difficult it remove it because the line is thin. But it happens no more frequent then mono for me (pretty rare event). The pros FAR out weigh the cons for this stuff, this is a no brainer.
I have heard good things about stealth and the new stren from guys that have used PP in the past and suffered some mystery break-offs which I have been luck to avoid for the most part. I want to try some of the others for mylsef. Just looking at the stealth...it is a lot thicker in dia then PP. I am worried about cansting distance reduction and water friction when fishing bottom. I have to say the stren looks excellent. just as thin or maybe thinner as PP (30=8 ish) and did not seem to have that waxy coating that PP has on there. They claim it is also more round then PP. (PP looks pretty round to me though

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I early in the season I plan to spool up with all three and give them my own taste test. For me the big advanages are sensivity, thinness, strength, durability, casting distance. The disadvantages for me have been sligthy more difficulty un-doing of windknots and make *sure* your guides are in good shape! This like does not like a guide with a nick or a crack in it. It will find its way into the crack and get cut, mono is so thick is is uneffected by a hairline crack. (these should be fixed anyway)
IMO ANY of these are FAR better then mono on a conv for casting or bottom fishing (which it is outstanding for). I have to say (FOR ME) it has spin cast fine on my newer reels. (Before you throw a 3oz plug into a gale with all your strength.....you just better protect you index finger...that line is really thin and will cut the tip of your finger just like a razor!) Also, have the shop install it for you properly. This stuff lasts a loooong time compared to mono. I leave it on all season, most guys leave it on for multi seasons without problems. (Don't try that with mono)
I have not tried it on my older (classic) spinning reels and will probably keep mono (big game) on them.
IMO this line will do for fishing what the "metal wood" and Titlest ProVII ball did for golf. its a whole new game now.