The analysis is excellent. The same goes for me. NTG5.5 is a terrible SATNAV for a wonderful automobile; it's disappointing enough for a Lada. Favouirtes only allows for 20 entries, Previous Destinations for only around 60, and when you add new entries, the older ones automatically disappear. While it's a pain to enter new locations via the manual interface, the Mercedes Me app does enable you to transmit locations to the vehicle through the Map, but when they'll really arrive is anyone's guess.
I did discover a way around the storage space constraints, however. That is, you should compile a list of places in your contacts, which is especially helpful if you want to drive overseas but don't want to bring along all of your UK-based connections. Simply compile a contact list in Gmail, save it as a.VCF file (compatible with Apple Address Book, Windows Outlook, People, and Windows Contacts), save it on a USB stick, and then import it into the vehicle through USB1 into the Phone/Contacts submmenu. There are 3,500 items in the car's Contacts directory. You may make waypoints by following a certain naming/numbering protocol, in which non-alphanumeric letters like "(" occur before the alphabet. Entering the proper address is the difficult part. When using a Contact Address as a destination in NTG5.5, you must always provide a house number and choose the appropriate language to define the address in. Google Maps, Viamichelin, and the Mercedes Me App Map are the three mapping applications I use while in Spain; all three employ a confusing combination of Spanish, Basque, and Catalan to spell addresses. Validating each address before relying on the fact that it is accurately recognized by NTG5.5 while you're on the road is a time-consuming and laborious process. Oh, and NTG5.5 doesn't like shortened entries like "Av." for "Avenida" or "Avinguda," both of which are valid in Spain. It's a lot of effort, but you can create libraries for several nations, save them on USB drives, and then just remove your current contacts and replace them with those from the country you're visiting. It's straightforward after you've set it up, but many of you will probably decide you'd rather purchase a BMW or Audi the next time around.