I am using Bottom Line in my LA right now for the first time with Isacord 40wt embroidery thread in the top. So far I am loving it and I especially like how much more thread the bobbin holds.
But Bottom Line is definitely a Superior Threads product. It is copyrighted and trademarked as a name brand Superior product.
http://www.superiorthreads.com/shop/...e/description/
If you are using a YLI product it is not Bottom Line. It may be their Basting and Bobbin thread which is cotton (bottom line is a 60 wt poly). Their website doesn't state what weight thread it is. YLI makes wonderful thread as well.
http://www.ylicorp.com/YLIQuilting.html
http://www.ylicorp.com/Basting&Bobbin.html