May be speaking for myself here, but the M-Series DAQ in USB forms have mass termination option (to connect to VHDCI connectors) and the X-Series do not. Why?
We have hardware that is already setup for the 68-pin cables, and I would like to take advantage of the portability of the USB, and the extended performance of the X-Series vs. the M-Series. Specifically I was comparing teh USB-6361 X Series and the USB-6251. The price difference is minimal for the added sample rates and extra counters. But without the mass term option, I am forced to settle for lesser hardware. This should be fixed.