this is the only P-line I have ever used and it was total garbage. I bought it in 12lb for swinging flies but it was so weak it broke on anything with barely any force. Made me feel I was fishing 4lb
http://p-line.com/line/fluorocarbon-coated/floroclear
If you do a search for "best 17lb mono mainline" on this site you can find the thread I started back in the summer or so of this year. If you read through the comments you'll see several guys reccomended the CXX-Xra Strong for mainline. I ordered a 600yrd spool from Basspro as they had a free shipping any amount promo at the time, but WSS and A&N etc carry it too. I am really impressed with the 17lb and decided to order another spool of 20lb which I use on my bigger baitcaster which I use the odd time targeting springs in faster water.
Like kalex60 commented about the Suffix Elite (which I've never tried) the CXX-Xtra strong doesn't seem to get the rough dusty feel that Maxima seems to get quickly. I LOVE fresh UG, which is why I still use it primarily for leaders, but I was finding for mainline is deteroriated too fast and I was cutting it back a lot, sometimes in the middle of day's fishing. With the CXX I found this much less of an issue and it seems to "perform" as well as the UG in other areas (memory, etc).
I would reccomend it 100%. Too stiff though to use on a spinning reel IMO.
I like to try out new stuff so although I like this line a lot when I'm out of it I think I'll try the Berkley Prospec, Seaguar Senshi, or Suffix Seige. A lot of guys seem to like all 3 a lot. I love the UG for leaders and it never let's me down! Too much confidence in it to change. Also like Berkley XT in green for leaders it's awesome too
When fishing for pinks, chum etc I tend to go through a lot of leader line so I use the XT as it's quite cheap compared to UG.