I think it's hard to compare Portrush to airshows in the rest of the UK. Yes it has an unrestricted fly zone and it's free but I think that is the only advantages that it has. Because it is free the organisers are restricted in the aircraft that they can attract to the show with the funds that are available.
Also because there is no runway it is hard to get close to the aircraft that are displaying - I once sat by the beach front and I'll never do it again - the aircraft were just to far out.
I just think it's great to be able to walk and static displays before the aerial displays.
Having said that I really do enjoy the Portrush airshow and give every credit to the organisers for putting on such an entertaining show and I hope they do so for many years to come.