In addition to the above, timing is everything too. It's always said that the earlier you get in, the better - get your place on the MSL. Now is a good time to join with so much recruitment ongoing. Those 320 FOs that joined at the beginning of this year are already at 70% on the fleet (i.e. 70% of 320 FOs are more senior than them, 30% are more junior) as there are so many coming in behind them, and the more senior pilots are heading off to LH or Command. Of course the usual caveat that it's aviation and recruitment could stop tomorrow, leaving you at the bottom for a few years.
Roster satisfaction also depends on what you're looking for. I think in the RHS of the 320 there's enough variety in lifestyles that it's fairly easy to get what you want. Some want day trips as they have kids to be home for, some want long trips as they commute, or want to see the world. Don't expect every weekend off, but if you're flexible it can definitely work for you.