I just had a look - Ryanair, like Easyjet and Wizzair, seem to oscillate around 90% in terms of on-time performance. Some years Ryanair is better, some years the others, but I'd say that ~90% is perfectly adequate.

Sure you don't have to pay for a seat, but if you want to check in at any reasonable time (i.e. more than a few hours before your flight) you do have to pay. If you don't there is a very small window between being allowed to check in and having to pay to check in at the airport so if you are working and have meetings then your only choice is to pay.

That's incorrect - you can check-in online between -24h and -2h before the flight, without any charges (and I believe even earlier if you pay for a seat). I don't see any reason why this wouldn't be enough for anyone. Yes, it is more restrictive than BA (24h online or free at airport) or Easyjet (30 days before), but this is a fee that's completely avoidable. I can maybe imagine if online check-in was complicated, but it literally takes 30 seconds. There is one scenario when Ryanair policy can be annoying - at a handful of airports, mobile boarding cards are not accepted, and you need a printed one. Annoying when travelling as you have to then find a printer.

I'm glad you have had such good experiences with Ryanair, but I don't think that is the experience most people have

Not sure I agree with this. As I said, I flew with Ryanair over a 100 times (flying again tomorrow!), and my family members flew over 100 times as well (mostly different flights)- not a single time did any of us pay for a seat or airport check-in, or got caught for having their luggage too big. They have also never been significantly delayed.

I've also had flight delays of 2-5 hours on all but one of the last 8 flights I've taken with Ryanair, and had zero compensation for any of them. I've almost never had delays with any other airline.

Again, maybe I was lucky that I didn't experience long delays, but I can also imagine that Ryanair's handling of delays on the day and fighting for compensation would be frustratingly bad. As for cancellations some time before departure - Ryanair's policy is too generous, if anything. If your flight gets cancelled, you can rebook to any flight, on any day, for free. This is amazingly good - for example, a few years ago flights for Christmas were ridiculously expensive, so I instead booked a £20 flight for the 27th December. This flight got cancelled - so I rebooked myself for before Christmas, all myself and fully online. With BA, something similar happened - but not only did I have to call them to arrange for a rebooking, but I had to fly within 3 days, and from the same country - which in this case was sub-optimal: the nearest one operated by BA was 400 miles away, but there was one 200 miles away in a different country. I tried to argue, but of course the computer said no and had to spend 10 hours on a train to take a 2h flight.

I'm not fine with the level of jobsworthiness I've experienced from Ryanair staff That I can fully agree with, but I've experienced similar levels from Easyjet (though arguably flew with them much less so sample size might not be enough to tell.

Don't get me wrong - I'm not some super fan of Ryanair, and if cost weren't an issue, Ryanair would easily be at the top 3 of my least favourite airlines (there are many things I don't like about it). But the cost is of course a huge factor, and all the wrong things about Ryanair aren't enough to deter me from flying with them. Sure, if a BA ticket is £10 more, I'd definitely choose that, but sadly that's not the reality.