Magus F8 vs Audio Nirvana super 6.5 alnico

This is my first post, so please be gentle!
I started building a copy of Nelson Pass speakers, I saw in a Sterophile interview of his. The open baffle design is quite simple. My question is this: I have listened to the Cube driver- amazing! But I also listened to an open baffle design with Audio Nirvana 6.5 driver and to my ears-regular, not golden one's, it sounded excellent as well.
Do you think that the cube f8 deserves the extra cost? Has anyone used Cube and Audio Nirvana full range drivers?
 
Firstly, welcome to our little abode.

In terms of the drivers -to be honest, it sounds like you have at least in part answered your own question. The truth is, it doesn't matter whether any of us think the Cube is worth the extra cost: it matters if you do. Since you've said you think the AN also sounds excellent, it simply comes down to whether the Cube unit you heard offered sufficient extra over that driver for you to justify the significantly higher price. That's really a personal choice: expensive wideband drivers can be superior to less expensive ones (this is not invariable), and setting all other considerations aside, if you choose well, you get what you pay for. But once you have reached a decent performance baseline, you pay increasingly large amounts for smaller gains.