Redrock only announced the microEVF last week, and already they have announced a change; it will include built-in HDMI passthrough. This makes it easier to have additional monitors attached to the camera, and is a feature that was announced in the upcoming Zacuto Z-Finder EVF (which was announced the day after the Redrock microEVF.) Redrock says the price remains the same.
Clearly this addition is in response to user requests; and possibly the competition. Also, it suggests that the product is still in very early development i.e. adding the HDMI would involved changing the case molding and circuitry; it's probably not just a firmware change!
Some people were bashing Zacuto's announcement as a rushed "me-too" because of Redrock's announcement, but it looks like they are both running to try and out-do each other!
Zacuto: Z-Finder EVF