First off, I sprayed the pieces Humbrol Metallic Silver as both an under coat and a base coat. This is an excellent paint which covers well in one go straight onto the plastic.
The Tamiya paint is much thinner and runnier than the gloopier Citadel and is much easier to paint onto the model. Unlike the Citadel, the Tamiya is often used by modellers through an airbrush to freshen up the colours on a model.
The Citadel paint was a pain. I put on two coats and it tended to form thick globules in recesses while running completely off raised areas. Even after two coats I had to do two extended touch ups and it still didn't look quite right.
In contrast, the Tamiya went on in one coat and only needed a couple of touch ups in raised areas.
Army Painter gloss varnish, painted on completed the build.
Tamiya make a complete range of these paints in all the main colours - I shall definitely be buying.