There was a piece in the Sunday Telegraph about colour fade with this product.
Apparently the colour wears off as it's only skin deep and the advice was to live with it as there was nothing could be done to rectify the problem.
Possibly something you could ask the supplier about?
I worked in the UK with a pattern imprinted company who used both mats and stencils to imprint concrete. Colour fade is a definitely a common problem when using mats but if you go for the stencil you should be fine. You do need to get them resealed every couple of years or else the colour and pattern will wear off.
was told depend on colour and how much traffic that area gets needs resealing every 2/3 years so am happy enough with that. seen a few house yesterday who has it and looks fab, one was done 3 years and one was done 5wks