Rio are good and offer great turnover a bit expensive and need a good pull to get them right.
I've used the cairnmore leaders and for the price are pretty good.
A while back I purchased a few Daiwa Wilderness leaders (4X) from a car boot sale, very cheap (iirc 75p ea) and I gave most of them away to friends and new starters, I tried the last remaining one this weekend and I rated it highly

, I don't know how long it will last but it offered great turn over, a good pull removed most of the spring and by the end of the day had become very limp and straight,and at that price was a steal, I've seen these at £1.50 and if I see anymore I will buy a few.
Regards, V..