So far I have purchased all GEX products, even the new Tropics package, even though I rarely fly there. I like what they do and in my opinion their textures are a very good way to vastly improve large areas at low cost. I have not used FScene but only seen comparative screenshots that show GEX to be better in the US and Europe, but this is just a screenshot and not a fully justified opinion.
In any case, although they plan, the GEX team have not yet covered Asia, except for some areas probably covered by their topics package and textures that are shared between areas. For Europe, north America, Africa/Middle East and the Tropics the GEX textures work very well imho.