I have been trying out a Samsung Galaxy Y Duos with Google Mytrack the last days. The accuracy of the recorded aGPS data changes somewhere between 3m and 20m radius of the actual position in mid-town area, which is pretty useless for finegrained recording, I would say. I guess open terrain data would not be much better in areas with large phone cells for the network assist. I just ordered a dedicated Visiontac VGPS-900 data logger for further track recordings, so next week I will do some track recording with both devices to compare accuracy.