What are the differences with this Olds 12 bolt rear from a bowtie 12 bolt

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=4592967846&rd=1&sspagename=STRK%3AMEWA%3AIT&rd=1

Besides the open rear, is it as good as a Chevy 12 bolt?

http://www.oldsmobility.com/10bolt-tech.htm
From what I gather, the 'O' 12bolt axle is actually a 10 bolt ring with a 12 bolt cover. It has an 8.5" ring and bolt in axles.
The corporate 8.2 12 bolt rear has a 12 bolt ring and 12 bolt cover, with c-clip axles.

Just from that info, it sounds maybe a bit stronger, but I have no real experience with them. You also might want to check parts availability.

it is basically a 10 bolt rear inside
gear choices are limited as are posis
better off looking for a 12 bolt

The corporate 12 bolt is an 8.875 , not a 8.2. The 10 bolt is an 8.2. The Olds rear is a 8.5 internally, and parts are hard to find. I'd definately skip this one, and get a Chevy 12 bolt. Just my .02$