As i know It works correctly on MTC units but it's still not good as an OEM car stereo.
MTC units handle correctly the pi-code of the radio stations so when it start searching it really search for a station with the same pi-code and higher signal.
Anyway sometimes it doesn't find any station or doesn't even start searching. This depend mostly on the territory you are driving.
I live close to Alps with many hills, up and downs and it work great.
When i travel through flat region it never start searching or find something wrong.
Then i believe that these Chinese units use only one PLL circuit while normal OEM ones use 2 of them to keep the old frequency until a new good one is found.
I'll update the first posts a.s.a.p.