Kind of depends on whether you normally eat at Mummycafe, travel by Daddytaxi, sleep and get your laundry done at Motelmumanddad.
Points to consider -
Package price at Perth is based on 45 hours in 6 months. If you can only fly at weekends you might struggle to fly the 45 hours in 6 months due to personal factors / weather / instructor / aircraft availablity / (you will not be the only student).
The cost of 40 odd trips Edinburgh - Perth - Edinburgh by car is about the same as a return flight from Edinburgh to Orlando.
You will have some landing fees for cross country navexes. Does the package at Perth include skill test fee and aircraft for skill test?
At OBA you will have transfer costs for pick up at start of course and drop off to Orlando airport at end. Accommodation costs will add about £400.
Travel to London or Belfast for visa interview plus visa, fingerprint, and TSA fees could come to about £300. Also cost of midweek day off work if applicable.
OBA include test fee and aircraft for test. There are no landing fees.
Groceries from Walmart are cheaper than Asda. At 19 you will not get into any bar or be able to buy alcohol (but room mates will help out).
Neither package includes text books, charts, fuel tester etc.
If you are living in the parental home and price is your only criterion then current exchange rate only gives OBA a slight edge.
If you want an intensive course in the company of like minders, OBA is the way to go.
Pay your money and take your choice.