Forced air heating system

I have a question regarding types of heating systems, in particular air heading systems.
I'm considering purchasing a second hand house (about 7 yrs old) that has a Forced air heating system, this system operates from both solar panels or from a gas boiler.
From what I have seen in the house, there are about 2 air vents in each room (I assume one bringing hot air in, the other bringing cold air out?). I don't have any details on the type of system installed.
Anyway, what I'd like to know is, how efficient an air heating system is compared to the normal radiator heating systems and if there is anything I need to look out for with regard to problems, etc.

btw:the house is in the haymarket,limerick - anyone owned one/lived there?
Any inputs would be most appreciated!
cheers! c.

I can't say I know what Irish systems are like, but when we lived in the US we almost always had forced air heating and it was always very efficient. Having said that, we also had well-insulated homes and that makes a difference too of course