TheOmegaCarrotFrom a technical point of view:
Modi 2 only has USB input, no optical or coax inputs.
Modi 2 takes it's power from the USB connection, not an external power pack (external power is probably the superior option).
Modi 2 has much better capabilities over USB (up to 24-bit/192kHz and supports asynchronous data transfer).
Modi 2 probably has better warranty/support (at least for buyers in the US anyway).