I am a motorhome owner with a vehicle over 3.5 tonnes. I thought truck maps would be a good thing. I discovered many apparent routing anomalies where I would be diverted from what might seem a logical route. The reason was because there are road sections where 'trucks' are not allowed'. A motorhome is not a truck! I have also tried using 'bus' as the basis of a profile but this is not always correct either.
Sometimes trucks over 3.5t are prohibited but again this may not apply to motorhomes. Height and width can also be an issue too and the truck version will help with these obstacles.
Careful editing of your vehicle profile to skew the speed on various classes of roads and the usage preference to avoid narrow roads. 'Other' roads are often un-navigable but many campsite are located on them. Don't disallow them entirely but give the lowest speed and preference 1mph & 1%. These will only be selected if absolutely unavoidable. Ensure that you then select 'fastest routing' otherwise these settings will be ignored.
Therefore to answer your original question I am considering reverting to the standard maps as I do not think 'truck' maps are worth the extra for me.
However if you have a 10m+ 7.5t+ American RV then you may want to consider them!