Replacing open diff. 8 3/4

I just ordered a powertrax lockrite locker. No sooner did I complete my order a dana power lok came up for sale close to me for $100 cheaper freshly rebuilt. Which should I go for?

It's in a 70 dart 360, 904, mostly street occasional strip with 26x8 Mickey Thompson slicks for track days.

Get the one with a warranty. Only $100? Peace of mind.