--I guess I would have more questions than answers... do you just want a line with similar properties as the current line you are using or do you want a specialty line?
--What # test ultragreen are you using now and what do you like or not like about it.
--That is what do you want different and what characteristics to you want to keep?: diameter, stiffness, abrasion resistance, stretch, high vis, coloured brown blue red etc.
--I think often people use ultra green as a default... and a very good one... that is if you are going to wander the river fish different situations and don't want to change your line as is common with flyfishers then a general purpose default like ultra green is a good choice.
--If you fish one area or target areas that are similar then you may want to use a specialty line... the farther you get from general purpose though the less situations you will be able to use the set up without changing.
--When boat fishing.. run&gun style I take several rod,reel and line combinations set up and ready to go.
--It is more difficult to change up on a river you at least need to take more than one reel or spool that can be relatively easy to change.. without fishing time.
--Depending on the rod used... line with more stretch can be used to soften the rod conversely less stretch can reduce or enhance hook up depending on the experience of the person casting and the river structure.
--I believe these multiple options are the reason so many stick with a proven general purpose line such as the ultra green.
--Like choosing a race car making the wrong specialty line choice can ruin your day or make you a winner. The best drag car is not going to win on a road coarse.