Pros an Cons: SBP v LBP

my car is currently a sbp /6 70 dart. 9" OE drums all around. i have in my side yard an 8 3/4 (unknown open gears) w/ lbp axles. i want disc brakes up front. the only wheel i want is either what i have or a mopar ralley so aftermarket rims, i could care less. are there any other reasons why it is better to go LBP over SBP? is handling better? is it cheaper to swap over to discs in front? thanks for any input in advance!

-ryan