I flew Ryanair for last week's trip to London. You just cannot beat their prices. But, I am curious to see how poor their customer service can get before people figure that they'll pay a bit more to use a rival airline.
The seats on the flight I was on were the narrowest I've ever had to use. And, there was insufficient leg room to allow me to get my legs in front of me. Now, I'm neither tall (just under 5'11") nor fat (about 177lbs) so I wouldn't have thought that I would be 'over-sized' for any airline, but I was pretty close the other day. Ryanair's seats don't recline and have a hard plastic back which makes it impossible to wriggle yourself into anything like a comfortable position. I could put up with it for one hour, but I honestly don't know if I could do two.
There are also no pockets on the seat-backs, which means there are no sick bags. This usually wouldn't occur to me, but due to the bad weather our flight was very bumpy and one of the children was looking fairly green around the gills. Fortunately, we landed without anybody losing their breakfast.
If I were traveling alone, I'd certainly pay a premium for more comfort. How much more? I can't say until the time to travel comes again.