Those look very nice - as Andy said, very clean paint work.
I always put sand on my bases before I prime my figures - it gives another layer of adhesive to hold the sand down, and I can scrape off any excess or misplaced grains after I glue or and before I paint, it lets me keep the figure just a little bit neat-er, no sand on the feet. And I also prefer the look of painted sand, so it works out pretty well.
-Alex