I use the generic serger thread sold at Joann for $1.99 a cone. I've had several cones with the "MaxiLock" name stamped in them, which makes me think it's the same thread.
Whatever brand it is, I like it for piecing on the sewing machine and for serging. If you're in no hurry, wait for it to go on sale at half off and stock up.
The Connecting Threads lines would work just fine on a serger.