Slightly off topic, but...
I have a GPS III Pilot which I use mostly in the US as the 172 I hire from The Pilot Centre at Denham (as in "172 in West London" thread fame) has a Garmin 250XL fitted, though I find the only time I usually look at it is to change COM frequency.
Anyway, I mainly use my GPS for flight planning and have noticed several anomolies with the database concerning sizes of airspace regions in that several ATZs are shown as being about 5nm or so radius. The last version I installed (went out-of-date last week) has Farnborough and Wycombe Air Park, among others, at this size (the latter is showing as overlapping with the London CTA!
This suggests that it cannot be used to guarantee you are flying clear of controlled airspace unless you have checked before your flight that the database conforms to your map. Anyone else find this?
Regarding other points put forward:
Why do you need to update the database every month? You only update your map once a year, after all. If there are changes to airspace, frequencies, etc, then you will be able to pick these up as you go from NOTAMs, etc, just as you would for your map. I only intend updating mine each time I move between the UK and the US. (Am I being terminally naive here?)
I agree that the feature of being able to "fly" your intended route on the GPS in the comfort of your armchair at home is great.
My GPS seems to have a selection of roads, railways and towns almost everywhere in the world as well as the Europe/Africa Jeppesen database, however it has NO map info for America! No towns, freeways, nothing except the state boundaries and state capitals. Is this what I should expect? Just seems a little strange to me.
BP