I use Royal, Outback, Isacord ,Robison Anton, Mills, QA and Birch. My machine doesn't seem to mind. They all work fine. I have quite a number of Maderia but they are small spools not mini cones.
I have been collecting Royal for several years. Outback (by Glen Harris) I bought the whole range,100 mini cones for $295.00 last year. I also have quite a few RA. Picked them up for about $1.28 per 1100yd. mini cones.
Yesterday I got 6 spools of Brother bobbin thread with a $40.00 off bonus coupon (spend $100.00) bought other stuff as well. Last time I bought batting and it already had 20% off before the $40.00.