Cost and strength were big factors for me when I built my Dana. Also the ability to reuse my current brakes helped as well.

I bought a junkyard F250 D60, 4.10's with a powerlok. I could have reused the stock parts and changed the side gears to 35 spline. Instead I went new and spent a few extra bucks, but it was worth it to me. I could resell the powerlock and gears I bet if I tried.

I have $1100 invested, Housing, billet housing ends, ring and pinion, axles, narrowing, set up kit, forged yoke etc. I sold my 8.75 for $650 making the total investment $450 for a rearend I haven't worried about for a minute since installing 4 years and 1000 drag strip passes ago.

My new ride has a 9", but it came with the purchase of the truck, and it is nice knowing if I need to change gears its going to be a quick project unlike the dana.