I got a free upgrade for my maps from Tomtom and first backed up my Navteq maps before putting the new Teleatlas ones on.
I found the Teleatlas to be very up to date on new housing estates etc, but poor enough on getting the old ones right!
For example, in Teleatlas 6.75, my small estate (11 years old) is marked as a series of roads but incorrectly named. The newest estate near me is fully marked and named very well.
In Navteq, my estate is named and marked correctly, yet the newest estate isnt marked or named.
Why oh why did they not just use an updated Navteq?
Anyway.. I reverted back to Navteq. At least it knows where I live.. even if the newest estates arent on it.