Hi,
Congratulations on your new camera. It's a nice model.
I use a Bronica SQ-B and RF-645 and love both cameras. Never used a ETR kit, but it is almost the "same type/system" as the SQ-B, only smaller and handier I guess.
I love the Bronica lenses: they produce beautiful images. Your 75 mm lens is the standard format lens for the ETR film size.
An extra film back is always nice for shooting B&W and colour simultaneously.

So, go out, have fun and get to know your camera.
And don't forget to post some images here ;-)