I really have to agree with Brian, especially if its on a baitcaster. The 65# will cast a little bit better, and have a hair less current drag, but it doesnt outweigh the extra abbrasion resistance of 80# vs 65#. 80# is just he way to go unless its for a spinning reel, then the 65# tends to cast much better, and is considerably more spining reel friendly.
Dfresh, what type of knots are you using? The only way your line will be breaking easily is if your line is scraping an abrasive surface while under load.
You also must consider there is no stretch.. your not pulling and stretching the line until you hit the breaking point… by the time your linemoves, it either came out of the snag, or broke.
I have yet to see any super line hold up to its rated strength on a scale.. swivels or hooks usually fail 1st. Super lines they rate the break strength at actual break strength, mono lines on the other hand usually break at a much higher poundage than actual line strength rating. So, if 40# mono has an actual break strength of 50#, and 40′ of 40# mono line had to stretch 7′ before it was stretched beyond its limits… compare that to PP that wont stretch an inch in 40′.. which line do you think is going to break 1st on an oversized fish with an improper drag setting? I guarantee it will be the superline every time.
There are advantages, and disadvantages to every line. To me, I prefer the super lines for the best performance, bite detection, and hook setting power…
but
I find myself spooling more mono back onto some of my rigs for the abbrasion resistence, and visibility. Its a heck of a lot easier tying on nuclear green line to a hook in the middle of the night than it is to see low visibility power pro.