I got my Numpad Module as a replacement under warranty for the one that came as part of an Everest Max Keyboard.
Like the rest of the keyboard, it looks and feels solidly built and well put together, but I wasn't a fan of how the numpad connected to the rest of the keyboard - felt too flimsy and likely to break if you were disconnecting and reconnecting it regularly.
It's a shame that I've had a Numpad Module fail within weeks of getting it.
And then having the replacement fail within weeks of getting it, requiring the whole keyboard to be replaced, if I wasn't getting a refund from where I bought it here in Australia.
My experience hasn't been great, which is frustrating because I really like what Mountain are doing, their service is phenomenal, presentation of their products is fantastic, and build quality appears to be very high at face value.
I hate giving it a 3 out of 5, but that's where it's at.