Hi, sorry for being late, not sure if by now you will have made your decision.
I'd say stay on air bags, much better ride comfort.
People go on and on about airbags being a problem, they're not if you keep on top of them.
Most often there's a hole or a crack in one of the bags, this can be caused by age or by off roading.
Once it has a hole it keeps the air compressor running full time, in time, running constantly the compressor breaks.
A replacement is expensive, once a new one is fitted and the defective bag is not replaced, the same thing will happen again.
If you have 4 good airbags and a good compressor then you will have a fantastic suspension system.
I replaced mine on my P38 with 4 Dunlop bags and had great performance from them in every way.
The other thing to think about is that if you go for springs you need to tell your insurance company as it will then be classed as "modified".
Cheers. Ron.