Aurifil 50wt thread is my absolute favorite for piecing. It is very smooth and takes up little in the seam so that my blocks are more accurate with it. It produces *much* less lint than other cotton threads. It is fine, so the bobbin holds more of it, making bobbin changes less frequent. Although it seems pricey per spool, if you compare how many yards are in a spool it is actually good value for what you get. I waited years before trying this thread because of the cost per spool, but once I tried it I won't use other thread for piecing. (I also love this thread for machine quilting on my domestic machine.)
If you compare a strand of serger thread with a strange of Aurifil, you will see some big differences. The serger thread will appear fuzzy; the Aurifil will be smooth. That fuzziness is what produces lint in your sewing machine.