I think that strong bold designs with 2 colour combinations work very well, I used to play cricket with a professional colour matcher. He put the revamped BP Green and Yellow together years ago, not that I could tell they had slightly tweaked their colours. He advised me on strong combinations such as Black and Gold and also as now used by puma Blue and Orange. A theme in a range works well as most brands use it and a simple colour switch can do wonders.
I think fluorescents were en vogue about 15 years ago and to me are "cheap" but all things go in cycles.
I don't see a massive amount of GN kit but they have a good market share, I think the forum holds a great position as it tends to spot trends early and the general feeling towards a brand here is a good future indicator for the market. We like to think we are above the marketing lures but I see more of it working here rather than less, albeit on a higher level.