Over here in Belgium, astro tracks are becoming more and more the standard. They all take the excellent Kampenhout track as an example (the site of the anual EFRA race). Allthough I prefer dirt or clay over astro anytime (I don't like the almost absolute grip), I can't really blame track owners : astro makes a track virtually maintenace free and very consistent.
10 years ago when I started racing, we had an all american style indoor clay track. It was a blast to ride on but it demanded A LOT of maintenace. For example you had to keep it wet all the time or it started to crack. After 3 years, the track owner reverted to astro.
