97maroon4x4

Alright so my rear diff is leaking a little and upon inspection the thing is rusty as hell, so im looking to replace it with but don't wanna spend huge $$ on aftermarket.
So is dorman a good brand? Im just not sure with it being $20 and aftermarket ones costing $100 to $200 plus
http://www.summitracing.com/parts/RNB-697-705/