I quite enjoy using ADF, dead simple to use. Useful for locating CBs too
Many ADFs are being decommissioned when they go U/S and most people don't use them anymore, but I still like using them purely for simplicity (sadly there are less and less around).
A lot seems to depend on the site's transmitter power. Many ADFs at airfields are low-powered locators and are only effective when within 10nm or thereabouts radius and seem more susceptable to interference from Wx and terrain. Higher-powered Tx sites (and hence longer-ranged) aren't as susceptable but can still suffer from the same problems. As mentioned earlier the aircraft's ADF Rx and the aerial/its position on the airframe also can be a problem.
Not too long ago I managed to pick up EDN once whilst way out past Dunbar on the East coast, usually I'm lucky to pick it up anywhere past the Eastern boundary of the Edinburgh CTA, but it was a very nice day Wx-wise, as I got close to the coastline however the needle moved towards Fife... perhaps a good demonstration of coastal effect.
Smithy