Enjoy your V.V., Greg; theyre a great little machine. Ive got one at home (with a depressurized portafilter) and another in the office (standard portafilter).
I used filtered water in my machine at home because Im told this helps slow down the build up of micro-particles inside the unit, and I flush it every few months with descaling solution using the regular brewing cycle. The office V.V. uses regular tap water (but it hasnt been around long enough to know whether this causes any real difference in terms of cleaning).
Ive found it necessary to occasionally manually clean out both the shower screen and the basket from time to time using a sewing needle (!) as some of the holes have become firmly blocked with coffee build-up that no amount of flushing will remove.