UE Diffs

[GorillaMaxx360]

I am shopping around for diffs and i thought i narrowed it down to the FLM diff gears with the great assembly diff cases. While i was on Ultimate Engineering.com i saw a 7.5 spider diff. Now i am not a pro at diffs but is seems the spider diff has like three times the number of parts and is like three times the price. What is the difference between the diffs. Is the spider diff considerably better in the performance area or are the diffs just stronger. What is the advantage of going with the spider diff over the regular aluminum diff case with steel diffs.