I've tried Power Pro and Sufix 832. Both of them are about to some in my opinion.
Strength - They are about the same. I caught a 200lb, 7' Nurse Shark on 50lb Power Pro. As long as you set your drag properly, it doesn't matter. You rarely if ever need that kind of breaking strength in freshwater situation...I don't care what anyone have to say. Have you even try to actually break 40lb line? It is difficult, especially if the line is not abraded. Personally, I bend out stout 5/0 hooks before I can break 60lb line...mono or braid. I've yet to have a fish snap 30lb braid for that matter...and I've put 30lb braid through its paces with salmon and 40lb rays.
Casting distance - Sufix 832 is rounder and I find it comes off the spool on a spinner reel nicer than the flatter Power Pro. But on a casting reel, it matters little.
Visibility - They are about the same, depending on the colour you pick and the water clarity. They both come in a green colour. If you fish crystal clear tropical reefs, both would be very visible. If you fish the muddy Red River, both would be invisible due to the turbid nature of the river. At the end of the day, add a mono (fluoro or nylon) leader and you have little to worry about visibility.
Coating - I find Sufix 832 coating to last just a tiny bit longer than Power Pro. With the coating on, regardless of brand, the braid tends to come off the spool a little easier. There's a plus and a minus with this. When you want the line to flow off the spool on a cast, that's a positive thing. When it gets windy and you don't want the wind to blow line off your spool easily, that's a negative thing. This mainly pertains to spinning reels, so again, for casting reel, it matters little. Without the coating, the braid tends to absorb more water faster though. For freshwater situation, it matters little. For saltwater situation, it can trap salt in your spool leading to faster corrosion of your spool if you can't rinse out all the salt (rarely can you ever rinse out all the salt).
Money - Power Pro is cheaper than Sufix 832...and that is an important factor to me because once in a while I have a need to put 300 to 500 yards on a spool. Between 300 yards of 50lb Power Pro and 300 yards of Sufix 832, I think the price difference was $8 the last time I saw them. For 500 yard spools, that difference is even greater, although I don't have a Canadian dollar figure to show you since it is almost impossible to get 500 yard spools locally.
At the end of the day, I find people are often trying to split hair when it comes to minor differences between braids. If your fishing success depend on that minute difference, then maybe it isn't the braid that you should focus on.