There are only a few colors in Czech seed beads that have issues with color-fastness. Transparents and Opaques are reliably colorfast. Coatings, such as Luster finishes can be less hardy.
Czech seed beads do have more variation in color with their "color lots" than Japanese seed beads, so it is always a good idea to purchase all you need for a project at one time.
There is also more size variation in Czech seed beads, but still much better than you see in cheaper China-made seed beads.