... its not cheaper haha its lighter but the 13" mbps are light as fuck too. Like that guy posted, apple has some really good refurb shit. MBairs have very slow processors and minimal ram, no graphics card either. If yuo wanna edit, get a refurb 15" mbp like this one:
the 15" is 2.2ghz quad core, has a graphic card and 4gb of rame (upgrade to 8gb yourself for 40 or 16gb for 80) while the highest mbair is 1.8ghz processor with no graphics card and 4gb ram. Really, you shouldn't buy a mbair for editing especially when for the same price, you could get a way better 15" laptop.