Hi Mike,
For me, each model is practically a means to experiment with something new. At work, I have several models on my overhead cabinet. Several of them depict aircraft with natural metal finishes. Each of those models was finished using different methods. One uses a metal powder. Another uses Model Master metallic enamels. Another uses Floquil. Another uses Alclad. The funny thing is that, even though each one turned out looking differently, I still like all the results.
I tend to pick the techniques based on what I happen to have on hand and also if I'm curious to see how one way looks vs another. There have been times where I was running low on Floquil so I switched to Model Masters. There have been times where a plane was very basic in its shape so I took it as an opportunity to try my hand at using foil. Some methods are more labor intensive or others just might be simpler to do. I can't say I have a "favorite" but I will say that it all is determined on what my mood is or how much/little I feel like putting into it at that point in time. It's whatever makes me happy at that moment.
Eric