Just for the record EZY does have loss of licence and a money purchase pension where they contribute 9% (isn't that better than BA for new joiners?). The roster is fixed 5/3/5/4 so you can do the math regarding days off. Three sector days must be very unusual as there are very few nightstops. 100 hour months also means that you will run out of hours at some point in the year...
I still would not leave Iberia though. First there is no guarantee that you will have a command in Madrid. Are you prepared to move to Latvia (or wherever) to get that command? secondly EZY is a UK company and if it suits them at some point in the next 20 years they will move out of Spain, Iberia is obviously not going to do that. Thirdly although things are tough at Iberia, because the erosion of terms and conditions, the reality is that they are still much better than elsewhere; you may be in for a culture shock. Lastly in Iberia you can look forward to a mix of long/short haul and flying different types, variety throughout your career in other words.
Perhaps you can ask for unpaid leave from Iberia so you can still return if you don't like the taste of the grass on the other side of the river.
In any case good luck