i love the threads from connecting threads- have used their quilting thread alot for the past couple years- i also purchase Aurafil from Fabric.com and verigated & specialty threads from Superior Threads. all of them seem to work well with my long-arm.
if you have not visited Superior Threads website you should- they have alot of free information- charts that tell you the differences in the threads- what needle to use with each thread- alot of trouble shooting help---a great (resource) site...along with offering a vast assortment of threads.