"Cheap, easy to pass and I don't know a single person who did it and hasn't come to regret that choice in the medium to long term."
It would surprise me if all those Spaniards flying for Iberia, Air Europa, etc really have come to regret training in Spain. - Maybe that poster simply doesn't know many people abroad...
While I have never come across anyone asking me where I did my training (did it in US, Ireland, UK, Czech Republic), I cannot comment on whether UK companies do ask, but I know that this is certainly not true in the medium to long term as stated.
A colleague of mine did his MEIR in the Czech Republic (where the appropriate aircraft costs no more than 220 Euro per hour with instructor) and got a job immediately on a 737.
I am certain that a Spanish rating is perfectly acceptable. All the best for the course! IP