As one of those referred to by IO540 who had a good experience, its fair to say I was doing the IR not the PPL.
However before I made my mind up, I jumped on a plane and spent a couple of days there taking in the operation, hired an aircraft with safety pilot and got a feel of flying in Spain and also suss out Jerez for when I was not flying.
If you are trying to minimise the cost of learning to fly to the minimum possible, I can understand why you might focus on the cost of landings.
A personal visit may may cost a couple of hundred quid could be a couple of hundred quid well spent in terms of peace of mind.
Trying to do things on the cheap often leads to it becoming more expensive in the long run. Frankly if you cannot afford to visit, then I suggest you cannot afford to learn to fly.
If things dont work out it is not always the school's fault. Some students think they just have to turn up and they will pass. Some students are unrealistic in their expectations, and some students are just not mature enough to do it.
Making a visit says , you are really serious not just a pie in the sky wannabe, it also gives the school the opportunity to see you and get a feel about whether you would fit in.
If you do go, prepare a list of all the questions you have, it would be a shame to arrive home wishing you had asked this or that.
At the end of the day, you need to make your own mind up.