Just want to second this and add some colour around it.

1 - Check out the history of the EI flight on Flightradar24 or similar to see how they're doing regarding punctuality and cancellations before relying on it. I do use EI regional where it makes sense - but I often have a £20 Ryanair back-up ticket for later as well.

2 - I've witnessed some really horrible handling of EI delays. Stuff like passengers spending 2 hours in a standing in a queue at the gate, after the scheduled departure time, with the signs saying "boarding" and no EI staff present. Flightradar24 was correctly showing the aircraft's location (in another country for much of this time) but no-one thought the poor passengers deserved to be given any information.