I used these for the first time today, and I'll keep this simple: they are absolutely bloody excellent and I will be ordering some more. Simple as that.
I've been using these for some weeks now and I'll say it again - these are the best leaders I've used - everything about them is right; butt/tip diameter, flexibility, small perfection loop and they straighten really well. Oh, and the price is excellent.
If you're gonna buy some leaders, buy these. Simple as that.