You want a supple line of between 8 and 12lbs it must have good knot strength and very good abrasion resistance. The one I use which is also fluro carbon coated is Kristonite and its served me well. There are many other lines on the market but if you pick one that has the above properties you wont go far wrong. A much cheaper option is "Daiwa Sensor" which a lot of specialist anglers use and swear by it. Havent used the Ultima Power Plus yet but I have a free spool from a magazine I might try for hooklengths, its had a few good write ups over the last few months.
i have 12lb ultima Pp as my winter mainline or a 10lb co-polymer (puddle pig) clear summer conditions mainline on my main baitrunners and if using standard mono hooklinks i'll use the same lines but lower b/s (8lb) or sometimes use ultima mainline with the clear hooklink line.
my roaming barbel gear ,uses the clear puddle pig line in 10lb or 8lb as main line on my other bait runner ot my shimano stradic coupled to either my JW barbel/quiver or JW avon quiver rods
but a lot of my rigs are combi-rigs part coated sinking braid,part mono/floro
i have found the ultima power + to be a excellent line ,especially on the trent with all its rocky bottom ,it has given really good abrasive Resistance ,and been very good supple sinking line thats given great bite indication.
As many people that reply, you are likely to get as many different answers. That's the beauty of angling, so much is down to confidence and what works for us. Me, I use Sufix Synergy, have done for some years now.