Hi Joe,
I'd get it, but I'm an enabler. I have a Necchi BU that has become my go-to machine. It's quiet and no-nonsense. I picked it up off of GW's auction as a pickup-only as the only bidder. Here's some general reviews of the Necchis:
From McKenna Linn (quilter, author, and moderator on a couple of vintage machine yahoo groups):
http://www.mckennalinn.com/vintage_sewing_machines.html
and some tutorials from her:
http://www.mckennalinn.com/sewing-machine-how-tos/
which includes info on drilling the hinge-pin holes larger if you want to put it in a Singer cabinet.
From Ed Lamoureux:
http://sewing-machines.blogspot.com/...necchi-bu.html
If you do get it, there are two different yahoo groups for them. The larger is called necchisewingmachineclub which has additional files and manuals in a subgroup called Necchi_Sewing_Circle. That's the group started by Ed Lamoureux and where I found a manual and a service manual for my BU. The second group is called necchifiles and was started by McKenna Linn.
Here's a blog post with pictures of a BU Mira with Wonder Wheel:
http://tammyscraftemporium.blogspot....i-mira-bu.html
And here's a demo from YouTube:
https://www.youtube.com/watch?v=ZBIw8JgRav4
Someone here made a post about a replacement "tire" for the Wonder Wheel (I think grant15clone?) and that he had to purchase a bulk amount of supplies to make them and he had extra. However, unless you're interested in making designs, you wouldn't really need the Wonder Wheel. It will still do straight and zigzag without it.
They are really good machines.
Good luck.
John