Flex 940 - defective right out of the box. I also determined that the turntable base was weak and prone to flex at tension. Returned it immediately and stepped up to....
Combo 910 - much sturdier machine. Terrible fit and finish; but capable of a good string job. Had it for 14 months and strung approximately a dozen rackets.
They still owe me the reel of string with the original purchase... but I'll be pressing my luck.