wots the costin on this mate?
About £12 from Halfords mate.
Better/easier than SRP by hand?
MUCH harder - it is designed to remove swirls rather than cover/fill them and won't leave any protection like the SRP will.
Personally I wouldn't attempt a whole car with it as it would take so long and would look stupid if you start and don't finish.
Naith, on you're black Megane you are looking at 2-3 solid days of work to get it done just as a heads up if you decide to get it!