I have flown with Ryanair many times now, and they are BRILLIANT as far as I am concerned. I admit that I am able to make good use of the cheapest fares due to being out of work, but the service has always been first-class. As for weights and sizes etc, just stick to the advised limits, why risk it if it will cost you dear.
Hand luggage is often looked at as you pass staff, and they may ask you to try it in the frame for size, but as I say just stick to the rules so you have no worries.
All (or a lot of it) of the bad publicity you hear about Ryanair is either jealousy of their outstanding success, or because someone has a problem that they themselves MAY have created, such as not reading all info on the website and breaching rules.
Obviously Ryanair will be at fault at times, but they are a big buisness now, and like everyone else they cannot be perfect. As far as I can tell, the well-known boss of Ryanair genuinely does do things to keep the prices as good as they can to benefit us.
DO NOT LISTEN TO ALL THE STUPID HEADLINES, JUDGE FOR YOURSELF ON WHAT YOU SEE AND FIND OUT IN PERSON.
LONG LIVE RYANAIR, FROM A LOYAL FAN.