I buy Aurifil from Tristan Thread, you can't beat the price.
Santa gave me many Door buster boxes of thread for Christmas.

I hand piece and only use YLI = ordered from Connecting Threads.

I like connecting threads thread and I just purchased a spool of Aurifil and love it too,but it is pricey.

I buy all the new doorcrasher cotton thread collections. Even the solid red spools. I never thought I'd use the red as much but once I got it I found it works with most scrappy quilts for piecing and quilting.