Low fares is their ONE and ONLY true point of differentiation. When that is gone - what airline would you choose?
I will choose Ryanair. Because their product is realy terrific - of my 36 sectors with them this year I had delay only once, and even that was only one hour due to snow on runway. Most of the time I had already been outside of a (usually convieniently small) terminal by the schedulled arrival time. I had worse experience with other carriers.
And I like free seating, I usually manage to get a seat that I like (with a good window position related to a seat).