I have a spool in my front '60 and I lincoln locked the 14 bolt.
Traction: Excellent and predictable (unlike some automatic lockers) All my wheels turn at the same speed even when they're not on the ground... unless I have a broken shaft.
Steering: With hydraulic assist and cross over I can point the wheels in the direction I want to go with ease. Actually getting the rig to go that direction can be a chore since the front end gets "pushed" in some conditions.
Cost: Next best thing other than welding the spiders. Lighter too!!!
Strength: This is the strongest part in my front end. This will probably outlast the housing itself.
Opinion: Would I put a spool in a daily driver? No. In my rock-crawler or mud-runner? Yes. When compared to a detroit in the rear and a limited slip up front, being welded in the rear and spooled up front provides more predictable street and trail behavior. It also increased traction, tire wear and my volume of broken parts.