Rear disk brakes To do or not to do?

So I currently have rear end apart, axles being drilled to lbp, and need to replace everything. I think for a few more bucks I should be able to convert to rotors and callipers! Any suggestions or do's and don't s good brand, bad brand?
Not sure if this should be under brakes or not , just lookin for advise and pics and rough idea of cost!