I started with the colored thread and used mostly the varigated threads. Usually I could find one that pretty well went with everything in the quilt. Then I decided to use a solid cotton and liked that look too. Just this past weekend I used the mono on the top and a cotton on the bottom and liked that for the particular projects I was working on. I even used mono for part of the quilt and then used cotton for the borders for one of my projects. So I found that what I like depends on the project I'm working on. I haven't had problems with any of them other than tension issues. I guess I just play around with the different options and have fun!