i've not had any problems with my connecting threads thread- so far- sometimes it is possible to get a bad batch- i've bought expensive ($18 a cone) thread at quilt shows just to find it broke every couple inches & was not usable---contact them- they will make it right-
i've been using their threads for a couple years now & have been very happy (although- i do not use the egyptian cotton threads- i've never had any luck with them-regardless of source)
if you want to see what other companies have to offer you could visit Superior Threads or Atlanta Thread Company- both have large selections & are good resources to have- i will still buy most of my threads from Connecting threads but i do at times get something from one of the others....Superior threads has a great selection of Verigated Threads-which i love