I had Inforad for three months (only got rid when my kind employer installed 'SmartNav' in my car).
Its OK - ish.
Plus points:
It's cheap.
Minus Points:
Around these parts, it had some of the speed zones set wrong in the database - for example, it would think that some 40MPH areas were in fact 30's = and would bleep its t*ts off until you slowed to 30.
Some speed cameras (new and not so new) were missed totally.
It's not directional - ie it will alert you to cameras on a southbound carriageway when you are going north.
Better than nothing, but more irritating than helpful in too many instances.