I have been very tempted with the alternative cheap USA option and have numerous quotes for the same hours that are indeed cheaper per flying hour however, there is a few things that make me more inclined to do it in Spain.
Spains airspace is pretty simple from what I've checked and has lots of similarities to the UK. It also works with skydemon to make life a bit easier but I suppose you can get forelight for the US..
The USA does also require learning a whole bunch of new procedures both flying and RT. It probably would be manageable to learn but what I have found is once you add up the cost of flights to and from, accommodation, renting a car, spending money for food and fuel (depending on dry or wet lease), it works out very similar to doing it in Spain.
I also must admit that I love going on holiday to Spain so it kinda gives the best of both for me!