I can see absolutely zero downside loading the disc. While Garmin is superior, and so are most other manufacturers navigation systems, since you bought the feature, might as well get the benefits. If you use it occasionally, it will do a decent job.

You will only gain with the disc in. Traffic information and current location information. I have my right hand side of the display that shows the coordinates, direction, and current road and town. I always find that to be useful.

I use the Nav in my 2008 X5 & we have a Garmin that we use in rentals.

Both use Navtec base maps. If you are using the same version (annual updates for both) there is no difference in the map.

Features between the two systems are different as is the interface software, Both will get you to the correct location (usually) however if the base map is incorrect neither will.

Base maps are updated annually. Our US road network has thousands of changes over 12 months. So until someone comes up with a way to correct base maps dynamically as construction changes occur this is not going to change.

Hope this helps.

There's no guarantee that a Garmin (or any other add-on nav device) will give you the absolute best routing for a given trip or situation. For trips of significant distance, I always do some reasonability checks on the suggested route (even when using Google Maps).

Load the Nav DVD, leave it in there and try it out.

This is not specific to the X5, but coming into Greensboro, NC from OKC I was sent to the wrong locations for three separate destinations (e.g. like the Sheraton). I have the latest dvd and had same problems with my mobile Garmin as this is a Navteq issue.

Anyway, the cover of today's paper in Greensboro has a team from Navteq that was trying to remap Greensboro with all the changes on major roads here.

Yes. I agree with you. This is a stupid question and adds no value what so ever. If the same logic applies, why not put another radio in the car because it's "better" than the one that come with the car? I don't want to sound harsh or attack you -- doesn't matter what NAV you're using, the data is for reference only, so they will alwasy have their faults. Teh only thing you can compare is Ease of Use. I do want to say however, that the idrive wheel is stupid when it comes to inputing info. Touch screen's got that beat hands down