I fly Aer Lingus wherever possible but Mannion has brought the standard way down, so if Ryanair take them over, there won't be a whole lot of difference for us customers.
Putting my Cork Airport hat on, my gut reaction is that Ryanair taking Aer Lingus over would actually be of benefit to us, because Cork Airport's unwillingness to cut a deal with Ryanair appears to have been due to EI's threatened withdrawal of flights (as they subsequently did to SNN). It could really shake things up for once, and would probably put huge pressure on Aer Rianta.