Made my opinions clear here - which summarises Spanish Training very well.
http://www.pprune.org/professional-pilot-training-includes-ground-studies/331098-truth-about-spanish-irs.html
For the record I work at a UK registered JAA school and conduct CPL training. Quite often I come across students who have a Spanish IR who then have to complete 15 hours on the CPL instead of 25.
Shocking is the only word which covers the standard of training - nearly every student requires considerable remedial instrument training - just to pass CPL skills tests - and would never pass a UK IR.
Multiple students stating they have never done limited panel, unusual attitudes.
The testing procedure is atrocious - with some stating they never even flew a precision approach for their test, and would land visually. Approaches made up in flight. Skills Tests lasting less than an hour. I have started keeping track of how many students describe their test as a "joke"
Subsequently quite a few students spend more on remedial training than they do by getting an IR in Spain.