basically, the cooking spray is a mixture of fats/oils to help you prepare meals (when used for baking - to prevent the pastries etc. sticking to the form or baking pan). So it doesn't really matter, if it's oil or spray, as long as it's used wisely. :)
I personally don't like the sprays, since they're completed with chemicals (not dangerous, at least according to producers, but still - don't like too many chemicals with my food). I use small amounts of olive or vegetable oil, if just frying (i spread the oil on the pan with a brush), or small amounts of butter evenly spread over the form/baking pan/ aluminium foil when baking (if want to make extra sure, that stuff don't stick, I also put a bit of breadcrumbs over butter).
Hope your cooking will work out smoothly! ;)