The 2012 MacBook Pro, by far.
The only upgrade possible for the Air is storage, ram is integrated to the logic board and can not be upgraded.
The mid-2012 has at least a i5 2.5GHz dual core CPU (some have i7, 2.9GHZ processors), can be upgraded to 16gb ram and standard 2.5 inch SSD's. If you are doing general things with it, such as web browsing, Office programs, etc., the 8gb ram you have is fine. If you would use it for photo editing, video stuff (be kinda slow with video but I manage with mine) 16gb ram would help.
Two 8gb ram chips I've bought used on ebay for less than $40 and a 500gb Crucial SSD is less than $60.
The only upgrade possible for the Air is storage, ram is integrated to the logic board and can not be upgraded.
The mid-2012 has at least a i5 2.5GHz dual core CPU (some have i7, 2.9GHZ processors), can be upgraded to 16gb ram and standard 2.5 inch SSD's. If you are doing general things with it, such as web browsing, Office programs, etc., the 8gb ram you have is fine. If you would use it for photo editing, video stuff (be kinda slow with video but I manage with mine) 16gb ram would help.
Two 8gb ram chips I've bought used on ebay for less than $40 and a 500gb Crucial SSD is less than $60.