Black Sabbath - Which Versions To Look For?

It's funny, the Castles do seem to have better sources, and on Vol. 4, they sound really good. The WB releases are a bit murky.

My problem is that I now have the box set for the Mini-LP's, which are EQ'd even more agressively than the 1996 Castles. I kind of have a mish-mash of releases:

WB:
Master Of Reality
Sabbath Bloody Sabbath
We Sold Our Soul

Castle 1996:
Vol. 4

Sanctuary (Castle) 2000:
1970-78 Mini-LP Box Set

As a pretty hard core Sabbath fan, I think I'll pursue getting the rest of the 1996 Castles, used. The redeeming thing about the mini-LP box set is the pricing on eBay comes out to about $5 per CD. Pawn shops are full of WB releases in the $3 range, so if I stumble on to clean WB copies, I'll get those as well.

As for Rhino's upcoming Symptom of the Universe release, I wasn't too happy with their Nuggets Box Set I purchased, so I'll be foregoing that. Gosh, it would be fun to have the first four albums "Hoffmanized". It could be titled as a "Breath of Death" release