Well EI only hires into the right seat A320, all 330 and command places are filled internally by seniority, so it really depends on if you want to go straight to long haul (Virgin) or wait around for 3 years flying the A320 to get back to the right seat 330, and possibly longer if the expansion cools down. Also depends where you want to be based, if you want to live in LON/MAN, Virgin is the better gig in town, if you want to live in DUB and move your family there, or commute from regional UK, EI could be the better gig. Really depends on the lifestyle you want and where you want your career to go. Jumpseating in Uniform on mainline Aer Lingus is free once listed on the crew manifest, with unlimited ID90's available to purchase for Regional flights operated by Stobart after 6 months service.
Also, keep in mind that although the Aer Lingus salary looks very attractive, income taxes in the Republic of Ireland are quite high, with a marginal rate of just over 50%. And expect to spend bout €800 per month renting in Dublin where there's currently an on going housing and rental shortage after years of reduced construction activity following the economic crash, and expect much higher car insurance premiums here as well, all needs to be factored into your decision.