Since I use Pix4Dmapper each day I'm happier from the facility of managing data in this software, especially points (MTPs or GCPs) and polylines. The only issue its the height precision. We cannot expect that it will give you 1 cm height when your GCPs have 1 cm precision in quality report. You can expect 3 to 8 cm height difference between model and points surveyed in the field.
Another is the positioning of GCPs. You should every 60 to 100 meters have one GCP or Check point to control the quality of your model , or if the area is to small at least 5 GCPs well distributed in the model.
Great peace of software but, steel missing point classification
Good Job everybody in Pix4D and thanks