After receiving the batteries I did some testing using the ISDT C4 battery charger and was positively surprised. Running the analysis program (charger runs through a complete cycle) the charger showed a capacity of 3350 mAh for both batteries which I ordered. Since it will probably not drain them too extreme when doing the test, the results are in line with the 3500 mAh stated. So far they appear to be in line with the datasheets and seem to be of good quality.
All good...