Very good and interesting post, some relevant points been made ref. tax position and situation of non residents, these are over comeable by setting up company structures. SLs or LTD companies etc. Each person would need to talk to fiscal representative and lawyer to find best structure.
With standing this , what is best for yields. Historically spain has been a low yielding country and a high ownership country. It has the highest home ownership in Europe, it was close to 80% versus some places like Berlin which is 85% renters! The complete oppersite.
The property prices were (and dropping) relatively expensive versus the income generation. ie. rent. The market was a bull market, and even the locals put their money into bricks and mortar with the belief it could never fail, now as we have had a bad market since 2007, yields may start to rise.
So what should you buy, the question should be, whom is your customer, are they locals, are they seniors, are they expats. How do I structure, - company versus buying as individual, do I use mortgage finance for leverage. Different areas have different clients, and different users, I do not believe there is an a typic answer. Other than buy cheap, and rent out for lots. How you achieve this is down to your buying strategy and your rental strategy.
It is like any business, you have to work the channels, to make the investment as profitable as possible, and that only comes with refinement in the process. And continually looking at the business model and tweaking it so it works effectively.
So the simple question of what type of property? It depends on your target customer, and target market.
The real question should be what is the best yield and return on my investment. instead? and compare it to other investments.