Most RBA's hold a lot less juice than any tank, of course, but you'll get better flavor. Everyone should own tanks and RBA's, really. Use the tank/s when out and the RBA/s at home.
In my experience; you can simply change to another flavor when your tank gets low. The flavors will be intermingled for a couple draws, but will then switch over to the new one, without tasting "off" in any way.