Yes, they are. I have a Becker Radio/Nav in my E39 and the MKIV in my E38. Now if only that Becker had a map display... perfect!

The things I like better about the Becker radio/nav are:
1. More natural voices than the MKIV, which sounds very robotic in comparison.
2. It gives you a lot of verbal information when it receives a TMC update and re-routes you.

What is better about the MKIV:
1. Visual map display gives you better chances to orientate yourself in relation to your location.
2. More POI information than the Becker, which is quite restricted.

Both are easy to install and integrate with the BMW sound system, CD player, other AUX devices, steering controls, etc.