I did my full JAA ME/IR with AM last April/May. I can echo some of the comments above, a/c went tech (I flew 3 different twins over the 15 hours) and I didn't manage to complete the course in the timescale quoted.
However this seems fairly common across various flying schools and clubs I have flown with (especially Florida schools i've experienced which are even worse). However to AM credit they are one of the few FTO's who stick to the financial budget quoted. When the a/c was tech for a few days I received extra sim sessions for no extra charge. The IR check was included in the price and covered the entire test no matter how long it lasted. They didn't charge fuel surcharges every time the price of oil fluctuated. They discounted my rent when it passed the quoted timescale.
Overall I was very satisfied with the course considering the price charged. As for the quality of Spanish IR's I find you take out what you put in, you can pass the IR test at a standard below that of some other JAA countries, but with time and effort you can gain the rating and be of an equally high standard of an IR taken with any other JAA state.
A spanish IR has never held me back, I gained it last may, had 2 interviews in july and started RHS in a jet in october 2007.
Hope this helps and good luck