I don't think it's a Ryanair thing, it's frequently experienced on all other airlines. Perhaps you've just had a run of some slightly firmer touchdowns. As what sounds like an experienced pilot you'll know that every landing is different. Everything can be perfect down to the last few feet and sometimes you still can end up with a bit of a bump. It can even be down to something as simple as touching down on an uneven part of the runway (ever been to Belfast City!?)
Dont forget that a smooth landing isn't always a good landing, especially if it's at the end of a float that has used up a considerable amount of runway.
As was mentioned above the 738 is a little trickier to get a smooth landing from compared with earlier 737 models. If landing on a short runway it's very important to touchdown in the correct part of the runway rather than floating trying to achieve a smooth touchdown.
As for the subject of aerodynamic braking, any aircraft with speed-brakes/spoilers (in laymen's terms the flaps that pop-up on top of the wing) will use them after landing to help slow the aircraft, reduce the amount of runway required and reduce the wear on tyres and breaks. This is often used in conjunction with reverse thrust. Even selecting idle reverse thrust will result in some aerodynamic breaking, with the reversers sticking out into the airflow.
Hope that give you guys a bit more info
